What is the MAF Test?


An objective measure of aerobic progress and an early-warning test for potential training problems.

Among the important benefits of using a heart monitor is the ability to objectively measure your aerobic progress. Objectively measuring improvement is just as important. Measuring aerobic progress can be easily accomplished using the maximum aerobic function (MAF) Test.

Without objective measurements, it’s easy to fool yourself into thinking all is well with training. The MAF Test tells you if you’re headed in the wrong direction, either from too much anaerobic exercise, too little aerobic exercise or any imbalance that is having an adverse effect on the aerobic system. (Stress and poor diet are two salient examples of this.)

One of the great benefits of the MAF Test is its ability to objectively inform you of an obstacle long before you feel bad or get injured. Your training will progress much more smoothly—and quickly—by regularly performing the MAF test.

The MAF Test can be done with any exercise except weight-lifting. The test can also be performed on stationary equipment such as a treadmill or other apparatus that measures power output.

To perform the test, you must first obtain your maximum aerobic heart rate with the help of the 180 Formula. While working out at that heart rate, determine your walking, jogging or running pace—the time that it takes you to cover a certain distance—in minutes per mile, cycling speed in miles per hour, or repetitions (such as laps in a pool over time), and make a note of it. This is the parameter you will test for improvement later on.

Below is an actual example of an MAF Test performed by walking on a track, at a heart rate of 145, calculating time in minutes per mile:

Mile 1       16:32
Mile 2      16:46
Mile 3      17:09

During any MAF Test, your times should always get slower with successive repetitions: the first mile should always be the fastest, and the last should be the slowest. If that’s not the case, it usually means you haven’t warmed up enough. (This is discussed later.)

The MAF Test should indicate faster times as the months go by. This means the aerobic system is developing and you’re burning more fat, enabling you to do more work with the same effort. Even if you walk or run longer distances, your MAF Test should show the same progression of results, providing you heed your maximum aerobic heart rate. Below is an example showing the improvement of the same person from above:

Miles    September    October     November      December
Mile 1       16:32            15:49            15:35                15:10
Mile 2      16:46            16:06            15:43                15:22
Mile 3      17:09            16:14             15:57                15:31

Performing the MAF Test on a bike is similar. When riding outside, pick a bike course that initially takes about 30 minutes to complete. Following a warm-up, ride at your maximum aerobic heart rate, and record exactly how long it takes to ride the test course. Your times should get faster as you progress.

Riding your course today, for example, may take 30 minutes and 50 seconds. In three weeks it may take you 29:23 and in another three weeks 27:35. After three months of base work, the same course may take you 26 minutes.

Another option is to ride on a flat course and see what pace you can maintain while holding your heart rate at your max aerobic level. This works best on a stationary apparatus. As you progress, your miles-per-hour should increase. If you start at 12 mph, for example, following a three-month aerobic base you might be riding 17 mph at the same heart rate.

Perform the MAF Test regularly throughout the year, and chart your results. I recommend doing the test every month. Testing yourself too often may result in obsession—you won’t improve significantly within one week.

If you walk or prefer other activities that won’t raise your heart rate to the maximum aerobic level, it’s possible to do the MAF Test without using the maximum aerobic heart rate. Instead, choose a lower rate for your MAF Test. For example, if you have difficulty reaching 150, your max aerobic rate, use 125 during your walk as the rate for your MAF Test.

The point of the MAF test is to help you chart your progress and to know when your aerobic system is getting off-course. Performing the test irregularly (or not often enough) defeats its purpose. If something interferes with your progress, such as exercise itself, diet or stress, you don’t want to wait until you’re feeling bad or gaining weight to find that out. In the situations where your aerobic system is no longer getting benefits, your MAF Test will show it by getting worse, or not improving.

Join the discussion 212 Comments

  • Rafael says:

    I’ve been using the 180 Formula on training for 3 months and perceived a improvement specially in the beginning, but then stopped making progresses at all. So I switched to anaerobic training and didn’t notice any improvements, but notice a increase in stress. I’m 38, run 3 to 6 hours/week at 127 to 137 BPM and adept of ketogenic diet. I stalled at 7:30 pace (minute/kilometer) or 12:04 (minute/mile). I really like the method but it’s a little frustrating right now. Thanks for any thoughts.

    • Rafael:

      There may be a variety of issues going on. It’s very hard to know what they are, unless you go to a health and fitness specialist for comprehensive examination. For example, muscle imbalances may be causing an increase in stress when you do anaerobic training. We recommend that you go to local experts to look at your musculature, gait, etc, as well as your nutrition. Although we are proponents of a ketogenic diet, your particular nutrient intake may require tweaks, given your medical history, present training, and fitness goals.

    • Martin D says:

      Intervals will help you get faster.

      • Martin:

        Thanks for your comment. Although intervals will help you get faster, you point it out like it is the be-all-end-all for training, and as if no other variables matter. For example, health and aerobic power help you keep that speed once you’ve become fast. An increasingly acidic body due to stress can create a wide variety of health problems. What we stress at MAF Fitness are the components of training that make fitness gains sustainable.

        Rafael’s comment very clearly suggests that he is experienced increasing stress levels when adding anaerobic work. Suggesting yet more anaerobic work for him is irresponsible at best.

    • James says:

      I see a lot of comments here about MAF training at HR xxx is too sow. Surely that’s an indicator that you aerobic fitness is poor. I’ve been training by pace and power for the last 9 years, and have plateaued for the last 3 or 4 years. After a disastrous 2015 season which I attribute to “less hours, more intensity” and my burning out, I decided to try MAF. I started in November with a HR or 112-122. I though that was ridiculously low. I was running at 10:00 mile pace. After 8 weeks of MAF training, with no intervals or anything, I’m now running at 8:50 pace at the same HR. This stuff works.
      MAF training WON’T make you a 400-800-1500m track star. Don’t look at it as increasing your maximum pace. I won’t. It will increase your minimum pace. You know, the one you end up at over the loner distances.
      When training with pace or power, you always want to run a little faster, ride a little harder. Personally, you always end up lying to yourself about how hard you can go. You end up training a little too hard. It’s just a matter of perspective. I know that if my HR goes above xxx then I will pay for it in 30 minutes or an hour.
      Anyway, maybe it’s not for everyone. You definitely have to check your ego at the door, but it’s definitely worth trying for a few months in your off season.

  • Hi Rafael, although you may take vitamins you just may still actually have a nutritional imbalance which is hampering your performance and improvement. The most common ones I see which you can do a blood test to check are: insufficient Essential Fatty Acids, L- Glutamine, B Vitamin Deficiency , Minerals like Magnesium, Manganese, and Zinc, Vitamin C or E or The amino acid Carnitine.

    Have an applied kinesiologist who is knowledgeable in resting aerobic and anaerobic function test you
    using Dr. Maffetones specific challenges. Making sure you strengthen on aerobic activity and do not weaken on the anaerobic challenge. If you do, they will check you for some of the above nutrients to see which corrects the imbalance found.

    Use the functional levels on a fasting blood test on this free form and I can help you spot which it is. https://www.myvits.com/WeakestLink/BloodTestForm.aspx
    Other causes may be hidden infections, food sensitivities, pelvic or foot imbalances, insufficient sleep or caffeine sensitivity impairing your liver and adrenal glands. An analysis using the Free Metabolic Assessment Form can help you find what is the weakest link at the same site above.

  • Doug says:

    I apply the 180 formula to my running. When I do the MAF test at the track, I warm-up first, then start. I run 1 mile, then stop and record my time. Then I run my 2nd mile, stop and record my time. I continue this for at least 4 miles, stopping each time in-between to record my time. Should I run each mile continuously or is it OK to stop briefly in-between each mile?

    Also, I am 60 years old. My maximum aerobic heart rate is 180-60=120. I have been running for many years with no injuries so I added 5. So my maximum aerobic heart rate is 125. My range is 115-125. My pace at this range is excruciatingly slow – even embarrassingly slow!!!! My pace is around 13+ min/mile. This was humbling. I went ahead and added an extra 5 points to my heart rate so I run at 120-130 so I could bare running this slow. I feel OK at 120 to 130. Is that OK or is that cheating?

    I want to see if this method of training can really help me get faster while running at my maximum aerobic heart rate. Right now, this seems impossible. I am so slow! I need encouragement to stay at it and give it time to see results for myself.

    How do I apply this method in a race? Say, a half-marathon or a marathon? Do I stay at my aerobic heart rate for most of the race and then go to my anaerobic state near the last few miles?

    Sorry for all the questions but I appreciate your input and guidance!

    • Doug,

      In a marathon many athletes tend to race best at 10-15 beats above the MAF heart rate. A half marathon will be slightly above this level, the exact heart rate is very individual. The key is consistent pacing, and not starting faster than your average pace for the event. After some trial and error you will know what heart rate suits a race distance best. You can very well start at MAF heart rate and gradually increase it throughout the race for great results.

  • Jonathan says:

    Doug makes some good points that I am also concerned about. I’m pretty new to running but have entered a 55km trail run on Borneo in August. If I follow the instructions and train at my aerobic rate (180 – 44) of 136 then I feel that I will be woefully under prepared for my big run in August. I’ve been out running 5 days a week since February with no real injuries, but most of my running is anaerobic. I often push my heart rate up to 175/180. I’m not covering massive distances at the moment though. Generally I run for an hour or so apart from once a week when I do two or three hours. The big issue here on Borneo is the high humidity and heat, which makes life very difficult when training! (Especially in the jungle on hills!)
    So – the big question is can I mix in an anaerobic session once a week?
    Many thanks

    • Hi, Doug and Jonathan.

      Thanks for your comments and your interest in the MAF method. I’m an editor on the site as well as a research assistant for Dr. Maffetone.

      Mark Allen, a six-time Ironman champion, took off time from racing to train by the MAF method—he had been plagued with injury after injury. At the beginning of his aerobic training period, he was running 12 minute miles. Slowly but surely, his speed began to increase, and he got down to his usual training speed. Only this time, he was running aerobically at that speed. The reason I share this story is to convey to you that sometimes, even the very very best have to take a long hard look at themselves, and start from scratch.

      That said, the 180-Formula is designed especially for those who are constantly injured and overtrained. Doug and Jonathan, if this isn’t the case for you, you don’t need to spend a long period of time building your aerobic base—it’s likely that you already have it well-established. Just remember: even the best athletes (actually, especially the best) do the majority of their training at an aerobic heart rate. They only do one or two days of anaerobic training a week.

      That is the basic MAF recommendation. If the majority of your training is anaerobic, getting injured won’t be a matter of luck; it’ll be a matter of time. But if you have a good base, one or two anaerobic days a week will keep you strong and powerful. HOWEVER, be sure to spend a couple of months a year (the winter is the best time) doing nothing but slow, aerobic training.

      I hope I’ve answered your question. Please shoot back a reply if you have any more questions or comments.


      • Ricky says:

        Hi Ivan

        A lot of runners who have come across this approach probably do have a good aerobic base and have got to a plateau, and maybe need some anaerobic sessions – this is where I think I am at not having improved my short distance i.e. 5k and 10k times for a year. In ‘High Performance Heart’ Dr Maffetone acknowledges this and suggests a maximum of 3 times a week, never two days running and a target HR of no more than 15 percent above MAF, then let the HR fall until under the MAF figure before repeating. Having said that if my main training aim was an ultra ( I have just run a 50km) I think I would do minimal training above MAF, my immediate aim is to improve 5k and 10k times.

        • Ricky:

          Everyone’s situation is different. What I recommend is that you use the MAF Test as a diagnostic: do a test every week (15 minute warm up, one or two miles at MAF pace, 15-minute cool down) and see if your MAF speed begins to drop. If your MAF speed continues to rise, you are doing the correct amount of anaerobic work. If your MAF speed begins to drop, cut back on the anaerobic and do as much MAF work as possible.

          I would recommend doing half-mile repeats at 5k pace once a week, and mile repeats at 10-k pace once a week. If your aerobic base can tolerate it, throw in an hour of strength training (core stability/mobility, deadlifts, squats) a week. Hire a good CSCS if need be.

          Does this help?

          • Ricky says:

            Hi Ivan. Thanks for your reply.

            Just a bit of background. I’m 51, run or cycle most days and have a 10k PB of 44.01 from last January having only improved by 30 seconds from the same race one year before, and a recent 5k of 22.10. The 5k time was disappointing although was on an undulating course. My recent 50k, also on a difficult course, was very slow in 5 hour 41 mins and that’s entirely due to lack of longer distance training. Although I have been a runner off and on for many years I have only being training properly for about 2 years because I felt I could be competitive for my age in running and triathlon.

            Yesterday I trained on the bike on a turbo trainer, warmed up then cycled for 25 mins very close to 134 bpm (i.e. 180 – 51 + 5), and was somewhat surprised to find that I was working quite hard and very similar in effort to my training without a HRM. I had to stop myself from letting the HR creep up occasionally but overall I felt that I was doing good aerobic training and not working too hard or too easy.

            Today, after warmup, I ran one mile at an average of 133 in 10:36 but unlike the bike session it felt slow. I rested for a few minutes then resumed at what I felt was a good aerobic pace i.e. approximately the pace I would try to run a marathon. The result was approximately 8.45 mile pace with an average HR of 139.

            Many of the comments on your forum seem to show similar results, that the formula is spot on for the bike but maybe needs a small adjustment for running, or maybe that is only applicable to older runners?

            I hope this is interesting for your research, it sounds like a great job to me. I shall follow your training
            recommendation and let you know.

          • Ricky:

            The heart rate is the same across all sports. The reason for that is because the level of aerobic (or anaerobic) function is linked to heart rate. So, even though you feel like the exertion is very little when you’re running (and this is a very common complaint), you’ll still start using your anaerobic system at the same heart rate.

            In order to get the best, most consistent aerobic and health benefits, there really is no way to run other than staying at the MAF heart rate. That said, after a few months of aerobic base-building, it’s perfectly fine to incorporate one or two speed days a week, in order to build more power and starting to prepare for race season (if you have one).

      • Lisa says:

        Thank you.

  • Dan says:

    I’ve been doing MAF tests for a couple of months but was initially just using my average hr for each mile, example 138 hr mile 1: 8:25 pace mile 2 at same avg hr of 138 goes to 8:33 and mile 3 at same avg HR is 8:40. Recently i have a purchased a better hr watch (polar m400) that tracks my max hr after i download the results. My question is, should i be using avg hr for each mile, or use a slightly slower pace based on a max hr of 138. These runs are typically more like a 9:00 min pace. I don’t have convenient access to a track, so i do my loop around a field that has a little elevation change…not a lot, but impossible to keep the hr exactly at 138. It may vary from 134 to 143 based on the elevation.
    I can see the value in focusing on keeping the max at or below 138, but doesn’t seem practical given the elevation variation. It seems like i am constantly looking at my watch during the run and would have to always either speed up or slow down based on the point in the trail gradual uphill or downhill to hit 138. Am i over thinking it, or is avg hr for each mile close enough?

    • Ivan Rivera says:


      I’m an editor on the site.

      Don’t overthink it, but try and make sure that your heart rate doesn’t go over your MAF heart rate. Because of this, Dr. Maffetone recommends running or biking ~5 BPM below your MAF heart rate. That said, heart rate spikes and heart rate variability are a fact of life, so many people go over for a few seconds each mile.

      The reason I wouldn’t just go by the average heart rate is because of this: what if for 40 seconds out of that mile you are doing 168 and another 40 seconds you are doing 118? You’re doing intervals at that point, not aerobic training. I would recommend that you pay a lot of attention to your HR monitor during one run, just to see how the hills affect your heart rate, and compensate accordingly.

      Thanks for commenting! Please shoot back with any new questions or comments.


      • Dan says:

        Thanks Ivan, I tried using my 138 target as my max on my MAF test yesterday. On the places in the trail with the gradual incline, I would just back off any time my HR approached 138, and tried not to let it drop below 130 on the decline sections. This worked pretty well. I only hit 140 once in the run and came out with an average of 131 for six miles including my warm up mile. Seems like this should be very repeatable as a test. I also found that I found that i can download the data to excel for comparison as time goes on…pretty cool.

        • I train in hot humid conditions on a track. The track is not flat and due to running with the hrm I have found the home bend is uphill and the bend out of home straight is downhill. I am talking about 3 to 5 beats per minute in these conditions. Add to that the shade as you run down the home straight from the stands and then out into the sun again 3-5 beats per min and then the fact that a bit of breeze can again make 3-5 beats difference. Then put in the fact that there is a delay in these factors registering on the watch and life is a complete nightmare. Heaven forbid If I kick a football back into the training pitch that can be 8 bpm on a hot day. I am relaxed about it and am just hoping that sticking to the system, my maf is 115 as I am a fit 70 yr old, will pay dividends on race day. I can run plenty of miles with no stress using this method and I am strengthening muscles I did not know existed. When I started using maf I had to walk often to actually keep my hr below 115 now I can shuffle along all the time for 15 K without a problem on a hot day.

  • SteveL says:

    I have a friend who I might be able to get interested in the MAF method. One issue she has is a high heart rate. She primarily does run walk as her heart rate shoots up high even with a very slow run. Thoughts?

  • ChrisA says:

    My only reservation with number formulas using age…is, what says my fitness declines that much over time? I understand it is a great place to start, much like personal trainers had been taught for years with the original 220- age then x % calculations . But basically it’s saying, regardless if I have had no decline in ability over a 10 year window, that I now have to train 10 beats lower..because the formula says so ( I know there is the +\- beats allowed for experience) .
    Yet utilizing a met cart… I can show the same RQ 10 years later…at the same HR, depending on current fitness level. Just like I found using the ‘max’ hr formulas, my ‘ attainable’ max (not formula driven..but actually seen during bike racing criteriums) shifted based on my power output changes throughout the season. I could only see a max of 178-180 at early part of the race season then 199 later during race season. Sometimes differences in ‘max’ whether I spent more time in the gym /leg weights or not.
    It is like calipers for body fat and charts. If I measure out with the exact same totals of mm per pinch as 10 even 15 years ago…the scroll down the charts to match ‘age’…those same caliper totals now equal a higher % of body fat…even though I am still totally the same pinch totals.
    Biolectrical impedance scales same thing. Stand on it with a typed in age of 35. Repeat with a entered age of 47 and whoa , I just gain %’s in body fat.
    Just my thoughts on variability. I use similar methods coinciding with breathing rates, PE, and such. It’s way more beneficial when you actually get to go run with a client. They can be huffing and puffing and say ” nah I’m good, this is an easy pace for me” when it clearly isn’t .
    Thoughts ?

    • Ivan Rivera says:


      I’m an editor on the site.

      Age is indeed significantly correlated with a decline in markers of aerobic function such as VO2 MAX. Formulas that use age are well-justified in suggesting that increases in intensity (and increase in anaerobic activity) occur in lower heart rates as time goes on. I chose the above article because the rescue populations described have presumably been active for a long time. Here’s another study suggesting that masters athletes indeed lose both aerobic and anaerobic capacity due to aging, while maintaining competitive levels of activity.

      In any case, I want to home in on your comment about “no decline in ability.” It’s very difficult to know (unless you’ve been expressly tested for blood lactate pre- and post-exercise) whether you have been increasingly supplementing a reduction in aerobic power with existing anaerobic channels, to maintain your ability levels. Since age affects anaerobic channels more than it does aerobic ones, I would place even more emphasis on developing aerobically as you age, because that’s really how you’re going to maintain and extend fitness. If you are indeed supplementing aerobic activity with anaerobic activity to maintain ability, at some point you’re going to see a reduction in health or ability—the beginnings of overtraining.

      I hope this helps. Shoot back with any questions.


  • paul blake says:

    I just finished my first week of MAF training and my times have gotten worse. Note that I do not run at the same time of day. Sometimes I run in the morning, noon or evening. Some days have been cooler with light rain and others in the 70’s and sunny. Could this be the reason for the slower times? My first MAF run was 14:28 second was 14:13 third was 15:25 and 4th was 16:06! I also bike at my MAF HR for 2 hours on the days I do not run. What should I do to get the times to come back down??? Feeling a little discouraged…..

  • Tom Scott says:

    When using your MAF pace as a predictor or guide for race pace (e.g., marathon pace = MAF – 15 seconds per mile), which MAF pace do you use if your mile 1 MAF pace is 30 seconds faster than your mile 5 MAF pace?

    • Hi, Tom.

      We haven’t established explicit guidelines for using MAF pace as a predictor, but if you click here you can read the ideas of Floris Gierman, one of our success stories. (Scroll down past the image of the blender to get to the right table). Floris uses heart rate instead of seconds to predict marathon pace.

      • Tom Scott says:

        Thanks. I heard Dr. Maffetone on a podcast saying they’ve found that people run a marathon at a pace of MAF – 15 seconds per mile pretty consistently. I was wondering if that was a first mile MAF or a 5th mile MAF or what number y’all are referring to when you say “your MAF pace”.

        • chad says:

          I have been using the MAF method to marathon training for the past nine months. A marathon I ran last fall (immediately before commencing my MAF training) was at 6:30 pace. I have only gotten my MAF test down to 7:43 average mile, so far. My mile splits during MAF tests are extremely consistent from mile one to mile five. The greatest differential between them has been four seconds (first mile has always been the fastest). NOTE:  I have been using 180 – Age + 5 beats (150 HR at age 35). 

          1)  Does the fact that my MAF pace has me at roughly 45-60 seconds per mile SLOWER than where I should theoretically be for my marathon indicate that my aerobic system isn’t fully developed?
          2)  What does it mean when your pace doesn’t slow?

          • John M says:

            Ivan, would you please comment on Chad’s questions. I have exactly the same questions. What does it mean when your pace doesnt slow? Is max heartrate set too slow? Is basebuilding fulfilled?

          • John:

            It means that your low-level aerobic base is well-developed. However, you can still keep building your base by extending your runs: you’ll see that your speed does slow when you go far enough. The more important question for whether basebuilding is “fulfilled” is if your increases in MAF speed taper off after continuous and steady increase over the course of 6 to 9 months. At that point, you’ll also notice that it’s “difficult” to get your heart rate up. Introducing 10-20% of anaerobic training into your regimen at that point, for some 2 months, will give you the power base necessary to once again ramp up your aerobic training.

          • John M says:

            Thank you so much! The test was 10km on a footballfield with very little variation each km, a few seconds. Ill focus on develop MAF instead. Im 3 month now on max 139 bpm, looking att another 6 then I imagine, my speed is not very impressive. Thanks again. Great job!

  • Arnau G. says:

    Hi! I’ve been reading about MAF Test lately and I think it would be great to test it myself as I’m a triathlete and my results are not improving despite my training.

    Do I need to stop training while I’m doing MAF Test? and, how often should I record my laps? ej. weekly, monthly, etc.

    Thank you very much,


    • Arnau:

      Thanks for your comment. For best results, what you can do is use the 180-formula to calculate your MAF heart rate, then see if you are above it or below it during most of your training. If you want to train in order to develop your aerobic system most effectively, it is recommended that you don’t train with weights or do sprints or intervals during the training period. It is best to check your MAF progress on a bi-weekly or monthly basis.


  • Bill Z. says:

    After listening to Dr. Maffetone on an Endurance Planet podcast and doing some preliminary research, I am interested in training with the MAF method. I am running in the NYC Marathon in November. I am hoping to qualify for Boston (3:55 for 61 year old male). I realize the MAF protocol is a slow build up process and that I will probably be running about 14-15 minute/mile pace, maybe even slower, to start. If I start doing MAF now, do you believe it is possible to get down to a Boston qualifying pace in 5 months? (I have been building a base over the past 6 weeks, 5-6 mile runs, 3 times a week, no long runs yet. I have run about 12 marathons in the past and qualified for Boston on two occasions. But I have not run a marathon in about 3 years due, for the most part, to various injuries incurred during training.) I switched to a high fat/low carb, no refined sugar, gluten free lifestyle several months ago and have stayed in a mild ketogenic state for most of that time, so hopefully that will help me adopt quicker (or not).

  • Adam says:

    Hey there,

    I am interested in beginning using MAF for myself, and then with clients after I’ve gotten comfortable with the process. I enjoy using the concept 2 rower and was wondering how I would measure my tests. Should I row a mile (in meters, 1609m) at my MAF HRV and measure from there, or am I looking at wattage since rowers also have this function.



    • Adam:

      I’d recommend that you stick to using heart rate for the MAF test: trying to reach a certain wattage during a stressful day will put your heart rate far higher than during a non-stressful day. In other words, this is why going by heart rate is so important, and why Dr. Maffetone has had so much success with his athletes by sticking to heart rate measurement.

  • Adam says:

    HR not HRV*

  • Paul says:

    Hi, I was wondering about Crossfit during the aerobic training period.. I usually do three sessions a week of Crossfit, and we definitely get our HR up higher than aerobic… My main focus is ultra running, so all of my training runs have been in the aerobic zone, but is the 3 day a week Crossfit Wod’s hindering my aerobic progress? The whole hour is usually not high intensity, just 10-20 minutes at the end of class for the “WOD”… Do I really need to quit Crossfit for a few months during the base-building/aerobic phase? (I don’t want to!) Or as long as all of my other training is low HR are the short 10-20min anaerobic sessions OK?

    • Paul:

      Thanks for your comment. The most important factor in correctly developing an aerobic base is to not do anaerobic workouts during that period. The effectiveness of your training will be in direct proportion to how exclusively you develop your aerobic base, by exercising at or below your MAF heart rate.

      It’s entirely possible to do crossfit workouts without going above your MAF heart rate. However, because of crossfit’s overemphasis on high-intensity anaerobic workouts, we don’t recommend it to most people, other than as a secondary anaerobic component to a primarily aerobic training. However, as I mentioned above, during the base-building component of any training, any anaerobic activity is not recommended.

      Our recommendation is to wait until after the period of aerobic base building, and then incorporate crossfit workouts once or twice a week. As an ultrarunner, you’ll benefit much more from a period of exclusive base-building than from strength gains made by crossfit workouts. Strength and power should be a component of any athlete’s routine, just not at the cost of an aerobic base, and certainly not without having first developed an aerobic foundation for strength.

  • Norman says:

    If one wants to also add swimming into to the training what accommodations need to be made? i had read before to minus 10 -15 off the Maf to accomidate for the water pressure can you please confirm?

    • Norman:

      You shouldn’t have to change anything for your MAF heart rate due to water pressure. Aerobic function is based on heart rate, meaning that it doesn’t change regardless of sport. What does change is AT (anaerobic threshold) which is subject to many more variables. Changes in AT, and not in aerobic heart rate, are typically what you read about.

      • Andrew says:

        Hi Ivan,

        I’m surprised by this. My heart rates/zones are certainly at least 15bpm less in the pool compared to running.

        I’ve read that this is because of the lesser effects of gravity, the fact you’re horizontal and also the lower temp in a training pool.

        I also read that you should take a base line heart rate beside the pool then get in up to your armpits, wait a bit and take another heart rate measure, what ever drop you find is your adjustment, so if my MAF is 143bpm my pool target might be 130bpm.

        If this is not the case then my swim training will not need to slow down all that much, which would be nice as I feel like I’m barely above a brisk walk with my running… early days 🙂

      • Andrew says:

        I found the source of this theory:

        “Heart rates when swimming are usually significantly less than when undertaking other sports on dry land. You may have noticed you feel to be working really hard in the pool but if you measure your heart rate it is much lower than you expect if you are used to monitoring your heart rate when running for example.

        The change between aquatic heart rate levels and dry land levels can be estimated. McArdle et al. 1971, suggested aquatic heart rate was 13% lower than dry land, Sova 1991, suggested a 17 beat per minute (bpm) deduction was appropriate.

        the maximum heart rate in the pool will be “220 – your age – aquatic deduction”
        From: ( http://www.swimovate.com/downloadz/SwimTrainingWithHeartRate.pdf )

  • Ian says:

    The basic concept is interesting and I’m considering it. However I have a few issues with it. First of all when I was in my early 30s my heart rate max when sprinting was 191 bpm. This is simply the highest figure I ever saw using a heart rate monitor. By last Spring at age 56 my max had dropped to 172 bpm. For the past 9 months I’ve been on a ketogenic diet (nothing to do with this site as I’ve only just discovered it) and my max measured heart rate has slowly recovered by a few beats each month and is now back to 191 bpm. At first I couldn’t believe this and thought it was faulty equipment – but it isn’t. (I use an EKG accurate Mio Fuse Optical HRM – and sometimes simultaneously with a Garmin chest strap) I bought Polar’s book by Sally Edwards at the start of the 90s and she explained the use of formulas for establishing max heat rates – but more recently I came across an article by her stating that if people train all their life then heart rate does not decline. The decline is only with sedentary people. I think that ANY formula is potentially very misleading and inappropriate unless the person is sedentary or cannot produce a maximal effort for some other reason. Personally I now suspect that heart rate decline is more to do with diet than with being sedentary – or perhaps a combination of the two! It would be interesting to hear if other athletes are having a similar experience. Testing max heart rate in my case involved repeat uphill flat out sprinting for at least 50m each time during a 10km run. Sure, my heart rate gets lower at the same effort level when I’m fitter – but my maximal attainable heart rate has now risen. For your information I’m a full time professional Alpine ski coach and compete in road cycling “cyclosportifs” – usually coming in the first third of my age group. (I cannot train cycling all year). Until going ketogenic I had weight yoyo-ing problems and lots of injuries and pains from endurance sports. I’m still looking for the best overall training approach though. I miss the carb “buzz” and don’t seem to recover so fast – but my results overall are improved. Just one other point. When my absolute max heart rate was at 172 (it had been slowly dropping for years) – I was able to sustain an average of 168 bpm for a full hour in a hill climbing race. That never made any sense to me – especially as the second time I did this I was already fully ketogenic. I have no health issues or history and a blood pressure of 110/60 at rest. This indicates even more to me that the science of heart rate use is very incomplete. Now that my max is returned to 191 (apparently thanks to ketosis) then this sustainable 168bpm figure fits the standard anaerobic threshold model far better. However, I have read that even top athletes can occasionally sustain 98% of their absolute max for an hour – so something is missing here.

  • Ian says:

    PS. My resting heart rate is 36 bpm when not drinking coffee.

    • Ian:

      Thanks for your comments.

      The MAF test is NOT about max heart rate. In fact, the reason that the 180-formula was initially conceived was because max heart rate is a very poor indicator of anything but your heart’s red zone. In other words, it doesn’t tell you anything about your health, only vaguely points at your anaerobic threshold (with a series of other calculations) and doesn’t consider your aerobic development at all.

      At the end of your comment, you mention that top athletes can sustain 98% of their absolute max for an hour. This is absolutely correct. However, the 180-formula isn’t really about the maximum heart rate at all, and it’s not for racing. The point of the 180-formula is for someone to figure out their maximum aerobic function heart rate (MAF HR), in order to develop the aerobic system maximally without producing the health problems associated with chronic high-intensity training. The aerobic system of most athletes is severely underdeveloped: this contributes to increased stress, increased anaerobic activity at rest, and the acidification and deterioration of the body, culminating in overtraining or injury.

      In response to how any formula can be potentially very misleading, I agree with your assessment, the keyword here being “potentially.” The 180-formula was reverse-engineered from decades of clinical study and observations, and has a very high correlation with the onset of lactate production in basically everyone that was studied. This means that it indicates the maximum level of purely aerobic work someone can undergo. (A formula that figures out your maximal heart rate, for example, is misleading for exercise prescription because it only tells you at what point you put your cardiovascular system in danger, not at what level you should be exercising to get particular results). In this same vein, the 180-formula is only intended to be used in developing aerobic function at the maximum level possible while maintaining stress levels at a minimum: it would be “misleading” for training anaerobically, for figuring out your lactate threshold, and for racing, because it is not intended for any of those things.

  • Ian says:

    can’t edit typos here! … “someTHING is missing here.” end of first comment.

    Also – should be ECG not EKG

    • Ian:

      EKG and ECG are interchangeable acronyms for “electrocardiogram.” It isn’t a typo. Thanks.

      • Ian says:

        Hi Ivan,

        Thank you for the response.

        I need more time to think over the entire approach here and I’m not criticising it. My initial approach when looking at something different is to subject it to questioning – and if it holds up then that’s a step in the right direction.

        You agree that formulas are potentially misleading – which simply has to be the case because every human is different. The heart itself doesn’t follow any linear mathematical behaviour – it is a prime example of second order non-linear, deterministic (but unpredictable) chaos theory – if we want to go down a mathematics route! I agree that for cheapness and practicality we can sometimes get useful approximations from simplistic formulas. However, whether you start from 180 and work towards a figure or start from 220 the process is the same and subject to the same errors…
        “The traditional formula for determining HRmax – age subtracted from 220bpm – can underestimate HRmax by up to 40 bpm in seniors, and starts becoming inaccurate already at an age of 30-40 years.” https://www.ntnu.edu/cerg/hrmax-info
        Your own results must be subject to the same or similar spread of inaccuracy. I’m sure you can supply standard deviations from measured samples across a population – but its only a statistic.

        At least max HR and min HR can actually be easily measured so the figures have some solid relevance to the individual. My only question then would be whether or not the way heart rate zones are devised from knowing both the real max and min rates is actually relevant or if it is another relatively wild mathematical guess. I’d certainly feel more comfortable being allocated a training target based on some real physical measurements and not on some statistical data. Statistics are often very misleading: for example my last bike race showed an average heart rate of 158 bpm for 5 hours – but most of that was anaerobic going uphill and “fat burning” going downhill. I was almost never aerobic – which should be the case at 158 bpm.

        I did once have Lactate Threshold measured in a lab but found that when I studied the results properly even that was not as clear an issue as I’d expected it to be.

        I explained in my first post here that my HR max has dramatically changed with less than a year of being constantly ketogenic (with additional cold adaptation). By not ignoring HR max and by structuring my program accordingly I’ve been able to witness this apparently remarkable and significant process. It appears to me that by ignoring HR max this process would (and has) been entirely missed by other ketogenic athletes.

        The fact that max heart rate is NOT age dependent means that no other aspect of training zones is age dependent – not even “aerobic”. People are not “statistics” and shouldn’t be slotted as “variable X” into any formula. There is a tendency for medicine – pushed by insurance- to treat “the population”, not the individual. Whether it be mass vaccination, fluoride in water, or Statin drugs – it categorically ignores the individual. It strikes me that the use of any “formula” beyond a very crude elementary level is an example of the same. That’s fine if it is clarified.

        With all of the above considered I suspect that the target here is to almost underestimate the training level and to err deliberately on the “low” side. This to me makes quite a lot of sense for a ketogenic lifestyle. Although ketones are molecules very similar to glucose I’ve not been able to find out yet what specific muscle fibres can exploit which ketones. Sure the slow twitch fibres burn fat – but ketones, where do they go? After about 3 months of adaptation even power lifters can have full power on a ketogenic diet so does this mean the mitochondria have altered to be able to exploit ketones – even in the two fast twitch fibre types? How can I at age 56 manage to produce (last year) a 98% max cardiac output for one hour – when in ketosis and not consuming carbs? Anaerobic activity is supposed to burn glucose and this was way above the “anaerobic threshold”. My body would not have that amount of glucose in store – so the question is – was this really “anaerobic” as is normally defined? What are the parameters we are dealing with when ketogenic? How do you really define the “aerobic” and “anaerobic” boundaries and are they even appropriate? I don’t mean specifically for me but for anyone. Is your “formula” and “aerobic” goal not at least partially a throwback to the chronic “high carb” paradigm?

        Personally I can run (not my main sport) at up to 160 bpm comfortably while nasal breathing (in and out). I consider that lactic acid is being compensated for in the body when nasal breathing becomes an effort and the body makes me pant through the mouth to expel CO2 – to maintain a bloodstream acid balance. That’s my anaerobic threshold. (It corresponds remarkably well with the standard zone calcs based on measured max and min HR) Given that my aerobic Zone is 145 to 159 – what is your recommendation for an upper level corresponding to your type of program? Is it 145 or 159? Interestingly lactic acid is not a problem in the body – it is a metabolite that converts to lactate and like ketones is a preferred fuel by the heart and organs. (I supplement with natural MCT loaded oils for ketone production and lactofermented foods for direct lactate absorbtion.) It strikes me that any training that does not develop the body’s use of lactate is not going to be very effective (Though I note that you advocate anaerobic training once a good aerobic base is established). We are inhibited by H+ ions – not lactic acid (lactate) and even drinking simple baking soda goes a long way to pulling the H+ ions out of the muscle tissue and increasing stamina through more effective use of lactate. Lactate unlike glucose is not insulin dependent so it compliments ketones very well.

        I like the idea of building a substantial aerobic base founded on a body functioning essentially on fat metabolism and ketones – though I cannot ignore either ingested lactate (usually with a strong probiotc source) or endogenous lactate. However it’s also known that when you increase effort you do not switch from one energy source to another – you simply activate more sources simultaneously. That means that so called “anaerobic” levels fully activate the aerobic level. Once again this leads to more questions than answers.

        It would appear that your system is addressing the tendency to develop the “anaerobic” level in the search for performance – while the base level is not yet developed. Resultant injuries might then cause this situation to become chronic. Easing off and building uniquely aerobic qualities might in some cases allow the person to develop further than otherwise.

        • Ian:

          Thanks for your continued comments and sober appraisal of our method. Formulas are indeed, as you say, just formulas, and the caveat that you mentioned in the comments applies to the 180-formula. That said, the 180-formula has a variety of “countermeasures,” if you will, such as adding or subtracting heartbeats based on health and fitness factors, as well as age. For example, a high-performing athlete without injury at 65 would have a MAF HR of 130 (180-65+15). This could account for the resulting performance and health benefits of a ketogenic diet such as yours, although not completely. The 220-formula, for example, makes no such considerations, and therefore would be subject to far more error than the 180-Formula (an assertion that has been corroborated through clinical experiments and research).

          To answer your question about the aerobic zone, the MAF heart rate of a 30 year old competitive athlete with no chronic illnesses or allergies, who has been competing without injury for 2 or more years, would be 155 (180-30+5), basically right in the middle of your particular “aerobic zone.” (Subtract the added 5 if you’ve had injuries, subtract 5 for allergies, and 5 more for chronic illnesses).

          I’m only extolling the virtues of the 180-Formula because it has been explicitly designed to overcome the 220-formula’s inadequacies, while pointing at the heart rate under which you can maximally develop the aerobic system. It describes a far broader population than the 220-formula, because of its built-in versatility.

          On a final note, your case seems like a particularly rare one. Maximum heart rate (as well as aerobic fitness) deteriorates very predictably with age. While no formula (and indeed, no battery of clinical tests) can describe every person, the 180-formula’s bet that heart rate drops with age is playing into very safe odds.

  • Ian says:

    Hi Ivan,

    Thank you for your considered response.

    First of all I want to point out a small error of my own – “160 bpm” is not my “anaerobic threshold” as I stated – it’s when my currently calculated/measured zones go supposedly from aerobic to anaerobic. The threshold (4 mmol) level is around 168 bpm (just because I know I can sustain that so there is no continued exponential climb of lactic acid.) However this all does make the data fit quite well with predictions. Science is all about predictions.

    You need to check your own arithmetic above! 180-65 +15 is only 130 bpm – not 145 bpm.

    This is where I have a slight problem because using the 180 formula my apparent level should be 180 – 56 + 5 which gives 129 bpm.

    My current “Fat Burning” zone is 130 to 144 and my aerobic zone is 145 to 159 – so this 129 figure wouldn’t even get me into the start of the fat burning mode. In addition the rules applied to a 65 year old puts his “aerobic” level higher than mine!

    20 years ago “formulas” were acceptable because nobody knew what they were doing – but I’m not so sure about that now.

    Here’s some current data from Sally Edwards – the specialist who wrote the first book on the subject for the Polar corporation…
    http://thesallyedwardscompany.com/sallyedwards/ (She has written 20 books and over 500 articles on the subject)

    Your maximum heart rate (Max HR) is a specific number, the maximum number of contractions per minute that your heart can make. There are a number of basic facts about Max HR that we need for reference:

    . Max HR is genetically determined; in other words, you’re born with it.
    . Max HR is a biomarker, it’s your individual number.
    . Max HR does not reflect your level of fitness
    . Max HR is sensitive to certain variables such as altitude, drugs, medication.
    . Max HR is a fixed number, unless you become unfit.
    . Max HR cannot be increased by training.
    . Max HR does not decline with age.
    . Max HR only declines with age in sedentary individuals.
    . Max HR tends to be higher in women than men.
    . Max HRs that are high do not predict better athletic performance.
    . Max HRs that are low do not predict worse athletic performance.
    . Max HR has great variability among people of the same age.
    . Max HR for children is frequently measured at over 200 bpm.
    . Max HR cannot be accurately predicted by any mathematic formula.
    . Max HR does not vary from day to day, but it is test-day sensitive.
    . Max HR testing requires the person to be fully rested.
    . Max HR testing needs to be done multiple times to determine the exact number.

    For us, there’s one more point to remember:

    Max HR is the best index to set an individual’s training zones, it’s the anchor point.

    (I’ve removed any publicity attached here as it would be inappropriate.)

    • Ian:

      Thanks for your continued responses. I must’ve not been paying too much attention to my math. I recognize all of the facts about Max HR that you discuss. I don’t understand how they are implicated in aerobic development, however. Regardless of where your heart redlines, your aerobic system can be trained or untrained.

      I wasn’t considering your age, I apologize. I just used 30 years of age for argument’s sake. the MAF heart rate isn’t about putting someone in a state that is “mostly” aerobic; it’s about developing the aerobic system at the exclusion of anaerobic channels. The terms aerobic and anaerobic have been ill-defined, which is one of the reasons behind the development of the 180-formula. For example, in the “aerobic” zone, below your LT, you are still using anaerobic channels: the LT is typically the onset of blood lactate accumulation, where production of lactate exceeds lactate processing. As long as lactate is being produced, you are using anaerobic channels. The 180-formula intends to point to a heart rate that excludes all anaerobic channels.

      That said, sure, the 180-formula is just a formula (the jump of 10 BPM from 64 to 65 is a problem, for example). To figure out a purely aerobic heart rate more successfully, you’d need a battery of clinical tests that look at markers of SNS/PNS activity, such as amylase and blood NO (nitric oxide).

      • SteveL says:

        Ian Rivera: I finally get it! I don’t know about Ian above you were responding to but now I do and thank you. The comment: “…exclusion of anaerobic channels. The terms aerobic and anaerobic have been ill-defined, which is one of the reasons behind the development of the 180-formula. For example, in the “aerobic” zone, below your LT, you are still using anaerobic channels: the LT is typically the onset of blood lactate accumulation, where production of lactate exceeds lactate processing. As long as lactate is being produced, you are using anaerobic channels. The 180-formula intends to point to a heart rate that excludes all anaerobic channels.”

        That put into place what the MAF method is about for me. Now I’m not going to sweat that MAF number like I have been thinking I might be cheating myself out of a few extra heart beats of training. Thanks!

  • Ian says:

    Here’s my current zone data – using the Karvonen Modified formula (Heart Rate Reserve based)

    Even though “heart rate reserve” is defined by measurement (Max HR minus Min HR) – the zone variation over the 9 (denoted 2 to 10) different formulas presented here shows it all to be a lot of guesswork!

    • Ian says:

      Hi Ivan,

      I hadn’t seen your earlier response before I sent my last one. I think you have clarified the 180 formula for me now. It’s an interesting concept “pure aerobic”! It’s pretty much what I thought – erring on the side of caution in a very ill defined area. If that gets results then that’s fine.

      Normally so called aerobic levels are established by using max and min heart rates to compute them from – with the min heart rate being a variable depending on fitness – giving “heart rate reserve”. You’d think that would make those measurable factors very relevant. However lack of serious definitions appears to render the entire exercise redundant.

      • Ian:

        You got it. For example, Dr. Maffetone uses it a lot for athletes who have been chronically overtrained and injured, as a way to continue training: developing that aerobic base without any of the stress associated with anaerobic activity means that you’l get back in competitive shape faster, and when you do you’ll be more resilient to future overtraining.

    • Yeah. It’s nigh-impossible to come up with a formula that works. %HRR is a very good indicator of where you are in the aerobic/anaerobic continuum though. Now if we can reconcile all those different formulas…

      • Ian says:

        I’ve taken a week to think over the issues here and it appears that your system is very much on the right track and holds up well to questioning.

        First of all – you mention “pure aerobic”. Well unfortunately that detail doesn’t exist. However I see what you are driving at. The anaerobic system works even when we are at rest and in fact it regulates the aerobic system to a large degree. All of the specific carbs used by the aerobic system are generated by the anaerobic system. On the other hand all of the carbs used by the anaerobic system can be created in the liver by fat metabolism (from glycerol). Being ketogenic mobilises fat to a degree not possible when eating carbs – so the interdependent aerobic/anaerobic systems are very much tied into long-term diet. Furthermore the only way to train those systems correctly is to isolate them – with very slow aerobic training and also very high intensity anaerobic intervals – when appropriate. Training regularly at or near the anaerobic threshold is only going to cause fatigue, inflammation, breakdown and injury – so that’s best left to bring together only on a race day performance.

        I figured out (at least for myself) how to bypass the “formula” issues. When running – after a good warm up – and using nasal breathing (both in and out) I find that at around 138 bpm breathing is so comfortable that it is unconscious and effortless. Anything above 138 bpm then I become aware of breathing and it is now a bit of work. This to me is the logical point at which lactic acid (anaerobic metabolite) is starting to rise above a level where it is not sensed by the central nervous system. Your formula calculated 129 bpm and other formulas based on measurements said 145. Rather than using formulas or even measurements the nasal breathing raises awareness of breathing and apparently makes this transition very physically noticeable.

        Only one week of training using this slow approach for distance work and then two days with interval training instead (I already have reasonably strong aerobic base) and my performance in racing has shot up amazingly. This is mainly because I’m not “fatigued” by the training. Muscles may ache form the intervals but it’s not the same thing. Also – my max heart rate is still climbing (thanks to ketosis and diet) and went up to 192 bpm (from 191) for the first time yesterday 5km into a 115 km road bike race (when sprinting for position) – which terminated at the summit of Mont Ventoux (The Giant of the South) in France.

        • Ian:

          It’s great you’ve made it work for you, and great hearing about your accomplishments. However, as far as your comment on “pure aerobic,” I feel that for the purposes of exercise prescription, “pure aerobic” is a valid enough term:

          You say that all energy that gets processed aerobically are generated by the anaerobic system. Are you referring to glycolysis? When oxygen is available in the cell, glycolysis produces pyruvate. When there is no oxygen, glycolysis produces lactate. So, even this first “anaerobic” cycle has an aerobic component to it, based on the presence or absence of oxygen. Because of this, we define “pure aerobic” as a situation where glycolysis is producing only pyruvate across the entire body, such that the entirety of the energy being processed within the body transfers smoothly from glycolysis in the cytoplasm to the Krebs cycle within the mitochondria.

          Of course, even in the best of times, some cell within the body will be lacking oxygen due to supply issues and so there will always be some lactate production, but there are situations where the overwhelming majority of the body’s energy (e.g. 99.99%) comes from pyruvate and not lactate. I feel justified in referring to these situations as “pure aerobic.”

          Whether this means that the anaerobic system is active (because, strictly speaking, it always is and therefore this is not “pure aerobic” in absolute terms) is irrelevant to exercise prescription in 99% of athletic situations.

          • Ian says:

            Hi Ivan,

            I didn’t write above that “all energy that gets processed aerobically are generated by the anaerobic system”. What I wrote was that all specific carbs used by the aerobic system are created by the anaerobic system.”

            The Anaerobic system produces Pyruvate plus 2 or 3 ATP molecules which are the “energy” of the Anaerobic system. This process is always anaerobic – it’s what defines it. Whether the Pyruvate is then used directly by the aerobic system (its only ever source of carbs) to produce more ATP or converted into Lactate – then converted back into pyruvate (in the liver) or used to produce more glucose again – is now a separate “aerobic” issue. The point is that the key powerhouse fuel for the aerobic system can only ever come from the anaerobic system – so it’s the relationship between the two systems that counts.

            If Pyruvate actually does get to a point where it constitutes 99.9% of energy then that actually tells us that 99.9% of our energy was supplied directly from glucose by the anaerobic system – because that’s the only source of pyruvate. I consider this situation however to be extremely unlikely (and undesirable )because at low levels of exercise fat and/or ketone metabolism would be very active aerobically and at high levels then lactate would become the primary fuel source for the aerobic system.

          • Ian:

            Thanks for your comment. I understand better what you mean by saying that both mechanisms are always active. Indeed they are. My use of “pure aerobic” isn’t about describing physiology strictly speaking, but rather in a way that makes sense to exercise prescription: judging by your definition (which is in strict terms correct), every mention ever of “exercise X is aerobic but exercise Y is anaerobic” has been wrong, and rightly so. But again, I’m speaking in terms of exercise prescription: I’m saying “exercise X is pure aerobic if such and such…”

            In other words, I’m defining “pure aerobic” for the layperson (and the fitness specialist) who thinks in terms of “aerobic” and “anaerobic” and prescribes exercise that way.

            But if you’re asking that I understand the physiology (and that I agree with you) and how my definition is not correct strictly speaking? I do, (I do), and no, it isn’t.

  • […] got to the point where I plateaued so started to look at different training options. First I tried MAF for a dedicated 3 month period. At the start of this period I had already been using ithlete to […]

  • Ricky says:

    Hi Ivan

    Someone has set up a Facebook group to discuss our experiences of using the Maffetone Method, I think everyone would appreciate your input into the
    questions and comments, it’s at


    if you are interested

  • CMG says:

    I have read that it is normal for one’s pace to decline during a 5 mile MAF run test. How does one interpret a MAF test where the pace does not decline at all?

  • Paul Blake says:


    I am currently running at MAF 2-3 times a week with 15min w/u, 1hr run at MAF and 15 min c/d… 2 times a week riding my bike 15 min w/u, 2hr (sometimes 3hrs) at MAF and a 15 min c/d….. also swimming for 1hr about 1-2 times a week. Is this too much? what would you recommend for optimum results? I am starting over from scratch with this MAF training and really want to do this properly. Also what should your HR be at w/u & c/d if my MAF is 141-151bpm. Thanks for any insight!!

    • Paul:

      Thanks for your e-mail. It all depends on how much training volume you’re comfortable with. Everyone’s different, and everyone has trained to a different level.

      All you need to keep in mind is the “why,” the key to aerobic development. The more stress, the more anaerobic you go, even when you’re talking about family or work-related stress (which is why all chronic stress is so bad for us). So, the point of MAF training is to develop the aerobic system. How much is too much? when the stress starts building and you find yourself needing to recover (which is when you start going anaerobic). That’s when you’re no longer doing true aerobic training.

      Your warm-up and cool-down heart rate should be some 20-25 BPM below your MAF heart rate. (For example, a typical warm-up to an MAF run is a very slow jog or a brisk walk).

  • C says:


    First of all thanks for an informative and well maintained homepage!

    A bit of background:

    I am a 33y old male with background in team sports who converted to long distance triathlon (Ironman) six years ago. 10+ races later and top of my age group placements (unfortunately based on 80%+ anaerobic training according to Maffetone’s definition) I was diagnosed with “Exercise Induced Hypertension” and instead of blood pressure medicine received an adapted Maffetone method prescription from my sport cardiologist. The heart rate limits I was given are:

    Swim 120bpm
    Bike 125bpm
    Run 135bpm

    The idea is to try this for a 6 months period (two months to go) and then re-evaluate.

    I am much disciplined about this given the potentially life-threatening condition I could develop based on my blood pressure and really makes me sad when things are not working out as they should.

    Initially I made good progress on my MAF test dropping 12% between test 1 and 2 (one month in between). However, the last 2 tests have been back to square one in terms of pacing. I have throughout this period maintained 12-15h aerobic training/week with nothing else stressing my system such as work/life etc and I feel much better in general. Unfortunately that does not satisfy my competitive mindset.

    The key thing which has changed is the weather/temperature. It is currently 10-20 degrees Celsius warmer today compared to 2-3 months ago and certain days I am reduced to just walking to not exceed my prescribed HR limits.

    Key questions:

    – Could it be that I am extra sensitive to heat/sun?
    – Is there any empirical evidence of this as it does not seem to impact the PROs that much based on hotter/colder races in e.g. Hawaii (more the wind that is a factor)
    – How can I ever improve my training effect if I am reduced to walking when it is hot?
    – The other thing which I have noted is that my HR is much more sensitive in the morning (up to 30% based on empirical evidence no matter if it is hot or cold). Why is that? Does that also mean that the training effect is less in the morning?

    Kind regards,


    • C:

      Thanks for your comment. The sun is a great stressor, so yes, I would say that the reductions in your MAF speed are probably weather-related. The reason the pros can do it is because they are hot-weather trained. Let me put it this way: in order to sweat properly, the body has to do a lot of things. First of all, it has to activate the skin, the largest organ in the body, meaning that the metabolic cost of exercise just rose. Also, it has to negotiate the need for water loss (for cooling) with water retention (for survival). Learning how to do this is a skill of its own.

      Actually, the training effect is the same. The reason you are walking is because the metabolic cost of training became higher. Your metabolism is still getting trained. Granted, you may be training different machinery (the skin vs. the muscles) but your body is getting conditioned at the same rate; it’s working to bring the skin up to speed. Before you get discouraged, remember that athletic performance isn’t about the muscles. It’s about the whole body. The whole body needs to be working together, and heat training helps bring the skin into the team. (This is why heat training is great for increasing race performance, even for cold weather races).

      I’m not sure why your HR fluctuates more in the morning.

      • David says:

        I’m also curious as to how to interpret MAF test results with increasing temperature (I train outdoors year-round). I’ve already noticed a plateau in absolute terms with my MAF test as I move from Winter into Spring. As Summer approaches, how should I interpret my MAF results? If they’re better or at least the same under higher temperatures I would take that as continued improvement. What about if they drop due to the heat? How will I know if continuing my current program is providing the right level of training? Does it mean I just need to stick to the same program until Autumn/Fall when the temperature drops to find out if its been working? That seems a long time to be in the dark. Or should I switch to an indoor treadmill to conduct the test so the environment is controlled?


        • David:

          Excellent, excellent question.

          Think about it this way: your aerobic power is essentially the amount of fat that you can burn for fuel. As temperatures rise, some of that fuel goes to power your cooling (sweat) system, which means that there is relatively less fuel left for your legs. While this means that your speed is slower, it does not mean that your aerobic system is burning any less fuel (less powerful). So you are still developing it.

          What I would do to be able to TEST any changes in aerobic function is to do a MAF Treadmill test in a place you know the temperature will be relatively stable throughout the year. While speed on the treadmill isn’t representative of speed on the road, you can compare two treadmill tests. So even if your speed on the road drops (or your treadmill speed is lower than your speed on the road), if your treadmill speed continues to rise, you know you’ve continued to make progress.

    • Paul Blake says:


      Thank you for the response!

      What do you mean by “why”? is it “why” am I doing MAF?

      Also is it common to have sore feet??? I have never had sore feet before from running. I use to run further that I do now and never had sore feet but this MAF has my dogs barking…. 😉

      Thank you for the response and the response to “C’s” question. Loads of great information! I have been staying away from heat training as much as possible because I have very slow MAF times right now. I am starting from scratch and not doing anything but aerobic exercise. MAF only. When it is hot out I basically have to walk which is extremely difficult being a competitive athlete. Your answer below has encouraged me to take on heat training even if it means walking. But man it’s tough when people pass you by that you know you could out perform ;-)….. again thank you for all your response to all the questions!

      • Paul:

        By the “why” I mean what are the particular goals of the workout. So, why are you doing this particular exercise but not another. But you can certainly extend that to asking why you are using MAF and not some other philosophy.

        It depends. There’s a lot of things that can cause sore feet. At my house I have a vat with gravel that I walk barefoot on whenever my feet are sore.

        You know, I love discipline. I advocate for being very disciplined in training. And when someone asks me why I’m not going faster (or when someone passes me by), I tell them and I tell myself “this ain’t the race.” I’m training MAF right now, and maybe they’re doing their tempo run. It’s a mistake to change my MAF run to a tempo run because my ego couldn’t take it.

        I run a 17:25 5k on a bad day. My MAF pace is 9 minute miles. When I’m doing MAF, and someone passes me doing a 7-minute mile, I lower my gaze and let them go. Just like they say to run your own race, train our own training. And remember: they’re not “outperforming” you. Part of exercise performance is the mindset, and part of the mindset is self-talk. When someone passes you by, all you know is that they’re going faster. Maybe that’s their half-mile pace. Maybe their house is around the corner. Maybe you’re on mile seven of twenty, and they’re on mile two of three. Maybe it’s your tenth consecutive training day.

        • Paul Blake says:


          Some of those things you said are what I also tell myself 🙂 thanks for the encouragement!

          I am doing MAF because I jumped into triathlon’s with no training and went full speed ahead into it. After several months I was not getting any gains in performance. A friend of mine mentioned MAF and it made sense, so I did some investigating and listened to several of Phil’s podcast interviews. I never built an aerobic base before, instead I went straight into anaerobic. So I decided to take a couple weeks off with no training and then start solely MAF training in the middle of May. I am going to give it a solid 6 months before I take on any anaerobic training and focus on next years Tri season. Right now my MAF pace is 13:43 p/m. It’s so slow but I am hoping to get down to your pace by November. Do you have any recommendations to make sure I achieve this goal?

      • Ian says:


        I was curious about your condition so looked into it a little. It seems from the little information and understanding that seems to exist about it that it’s not really the exercise that’s the cause – that’s more of an effect than a cause. It seems connected with a problem of the ability of the cells lining the blood vessels and arteries to allow expansion. Some sources attribute it to free radicals and a possible lack of vitamins E and C. However I know that the one thing for sure that dilates arteries best of all is nitric oxide (NO). You can increase NO by strict nasal breathing as it appears to be manufactured behind the nasal passages. Also “restricted breathing” (in and out through the nose) increases CO2 tolerance – raising carbonic acid in the blood in general – which then releases a better oxygen supply to tissues and organs – and also causes more increased vasodilation and improved circulation.

        I’m assuming that you are already on a fully ketogenic diet anyway – so you are not stressing the system with insulin through excessive carbs (demanding more vitamin C and causing more free radicals). Just my tuppence worth – no idea if it can help or not.

        • Paul Blake says:


          I actually replied to your earlier post several days ago but for some reason I’m not seeing it. To answer your question about my “why”…. I’m doing MAF because I jumped into triathlon’s with no base built. I went from zero training to doing triathlon work and after several months I was not getting any faster and growing frustrated. So I am now completely resetting and soley doing MAF for 6 months and nothing else. I was called “super hyper competetive paul blake” by my general manager who used be a triathlete haha. I really want to be the best I can be and feel this is the right direction. I tell myself some of the same things you said in your post and that’s encouraging to hear from a fellow MAF-lete. 😉

          What advice can you give me to achieve maximum results by December? I would love to be at a 9:00 MAF pace. Even 10:00 would be great. Right now I am about 13:45.

          Also another is having my heart rate spike during workouts. Will this ruin my MAF workout? As soon as it spikes I walk and get it down immediately but this happens several times during workouts. I really do not want to waste any workouts and maximize my results so whatever you say I’m on it!

          Dude, thanks for going the extra mile and looking into the feet thing! You are a rockstar! Yeah I will try breathing more through my nose and look into the vitamins as well. Like I said it’s strange because when I used to run faster pace for longer distance several months ago my feet never hurt.

          Iam not on a ketogenic diet but if it will help me I will. Is there more info on the website? Is it a diet you are on? If so, how is it working for you?

          Again THANK YOU for all of your input it is much appreciated!!

          • Paul:

            Sorry about that. I’ve been at a family outing so I’m not as on top of my responses as usual. The best way to get faster at your MAF speed is to train diligently. Remember that Training = Exercise + rest. Getting fast is a matter of adapting correctly. For a lot of people, the barrier to adaptation is that they don’t rest properly, not that they don’t train properly. Mike Arnstein, also known as “the frutarian ultrarunner” talks about how the most important factor in his recovery is sleep. Meaning, for all intents and purposes, “recovery” really means “sleep.”

            Getting your sleep figured out is probably just about the most important thing you can do to keep improving on a consistent basis. That said, what MAF is all about, and one of the big things Phil stresses, is that overtraining, and a lot of the health problems in athletes, have to do with the fact that most athletes go at it too fast. I can’t really tell you how to ensure that you hit your target by December. But what I can tell you is that if you cheat, or find the training philosophy that promises results no matter what, you’ll jeopardize those results come January or February.

            You can’t rush sustainable fitness gains. It’s impossible, literally. Your fitness will crumble around you if you do.

            I am on a pretty low-carb diet but it’s not necessary for it to be ketogenic. As an endurance athlete, the most important thing is to train your body’s fatburning ability. A 20-30% carb diet will really help with that (as opposed to a 40-50% carb diet recommended to most athletes). The thing is, you want to incentivize (but not force) your body to burn fat instead of carbs, in order to develop its fatburning capabilities when you’re training endurance.

            There’s an axiom in systems thinking (a sustainability and business management discipline) that says: “don’t push growth. Remove the limits to growth.” If you think about training that way, and you find the limiting factors, the bottlenecks, an the barriers (and remove them) you’ll develop athletically far more readily and far faster (and far more consistently) than if you found every little training tip or trick. A lot of the time, those bottlenecks exist in the form of stressors, lifestyle habits, and even social or work pressures, more than they do in the choice of particular workouts or particular nutrients you do or don’t get.

  • Rafael says:

    Hi Ivan,
    I want you to know that I really appreciate the quality of your comments.

    I was fortunate to be chosen as one of MAF app beta-tester and what I’ve found interesting is that there was a tip in it regarding volume that I don’t remember reading in Dr. Maffetone’s books: to have one training per week longer than the average daily run.
    I personally have some difficulty finding the best volume for this training method. So what’s considered a optimal volume to train (considering that I’m a little susceptible to physical stress) in order to achieve improvement?
    Thanks for any thoughts.

  • Thomas says:

    Good Morning, Ivan-

    I am writing to see if I can get a little clarification on the MAF method, as it applies to me. First, a little background:

    I am 45 and have been competing in endurance events (marathon, half-ironman, cycling races, etc.) since 2007 and have applied a basic training philosophy for the last couple of years: to keep 70% of my training in a lower aerobic state. To make sure that my training was proper and not based on an arbitrary formula, I had a lactic threshold test completed while running.

    My vitals: My resting HR is around 55, I feel that this is important to know. My HR is 145BPM is when I reach ‘aerobic’ and 192BPM is my ‘lactic threshold.’ 182-191BPM is my tested MAF. So, it appears that as long as I stay between 145 & 181 I should be able to run for a long time. I train 70% of the time between 145 & 155 BPM.

    Based on the MAF formula and my years of conditioning I should run until my HR reaches 140 (180-45+5), but I don’t reach an aerobic state at that pace.

    Where would you recommend that I train? 140BPM is slow, but I find it almost impossible to stay below that with my genetics. Also, I haven’t been prone to injury due to training.

    One more item to note, I started the 14 day fuel source switch yesterday (July 13).

    Thanks for your time and assistance!


    • Thomas:

      Do you mean to say that 145 BPM is your aerobic threshold and 192 BPM is your lactate or anaerobic threshold? If so, then the 180-formula is spot on: it should put you just below your aerobic threshold.

      Remember that your body is always using the aerobic system, unless you are training at a higher intensity so that you are only using the anaerobic system. In other words, even at 140 or at 55 BPM you are using the aerobic system. The aerobic threshold, which is what I think you are referring to when you say “aerobic” (people’s “aerobic zone” is between their aerobic and anaerobic threshold) is the moment where your body starts producing lactate, but it is still able to process that lactate without it accumulating in the bloodstream. The anaerobic (or lactate) threshold is when production of lactate is so great that it begins to accumulate.

      The importance of training at or under your aerobic threshold (at MAF pace) is that since you are not producing any lactate, your tissue is receiving very little wear and tear: lactate is acidic, meaning that its presence causes tissue to wear down at an accelerated rate.

      HOWEVER: if you haven’t been injured, and most of your training is majority aerobic anyway, you are probably doing just what your body needs. That said, I would still do the MAF test once a month to see if your speed under the aerobic threshold (at the MAF HR) is rising or begins to drop. If it starts dropping, that means that your aerobic system is slowly atrophying. Continuing on that course will take you towards overtraining. In other words, you can use the MAF test as an early-warning tool: if your speed drops, you are experiencing too much wear and tear. It’s time to exercise below the aerobic threshold, without any lactate production.

      Congratulations, Thomas. It seems that you are already making all the right choices!

  • […] @ MAF. Saturday – sick. Sunday – jog to the local track, 5 mile MAF Test, jog home. The MAF Test is simply an objective measure of aerobic progress. The idea is to perform the same activity on a […]

  • Eric says:


    I just started reading Phil’s endurance book. The holistic approach and low HR training really appeal me so I decided to do most of my daily runs @MAR. That’s what I’ve been doing for the last four weeks, since I’m 44 I targeted my MAR @ 136bpm. Yesterday I decided to take my first MAF test as part of my Sunday long run, outdoors, on a flat trail behind home. I was rather puzzled by the inconsistency of the speed results despite maintaining a pretty consistent HR. I had a 20min warm-up (from 96bpm to 136bpm/2km), then ran 16km @ MAR, then 1km cool-down (15min). Here are my times (note these are min/km) and laps are km.

    No. Duration [hh:mm:ss] HR avg [bpm]
    1 00:10:39 109
    2 00:08:44 128
    3 00:07:39 134
    4 00:07:31 134
    5 00:07:11 134
    6 00:07:20 135
    7 00:08:02 135
    8 00:07:24 135
    9 00:07:50 134
    10 00:07:29 134
    11 00:06:59 134
    12 00:07:03 133
    13 00:07:14 134
    14 00:06:59 134
    15 00:06:58 136
    16 00:06:56 135
    17 00:06:57 136
    18 00:06:54 136
    19 00:07:40 132

    As I understood from the reading, my times are supposed to speed down after warm-up and here this is exactly the opposite, km4 is faster than km3 and km5 is faster than km4.
    Now the weirdest part, from km11 time is cut by 30s and my fastest lap is km18. How does that make sense ?
    One explanation I might think of is that I took 20g maltodextrin about 45min into the run and km11 starts at 1h20 into the run. Given the digestion time of maltodextrin being 30-45min, would that make sense ?
    Should I avoid taking carbohydrates at all during long runs if training @ MAR ?

    • Eric:

      I think that your analysis is spot on. Because of the way that you speed up at the beginning, I can also tell that you have a very well-developed low-level aerobic base. Good for you. The only reason you should avoid taking carbohydrates during your long runs (and it’s a good one) is because you are trying to gear your aerobic system to pull fat out of your body and burn that. If you fuel it with sugar, although you may be training the aerobic system, you are not training fat metabolism along with it. In that sense, you may turn your aerobic system lazy, and make your speed and endurance a function of how much you can fuel, rather than a function of how much fat you can burn.

      There’s a quote in systems thinking that I love: “any long-term solution must increase the capability of the system to shoulder its own burdens.” In effect, by fueling with maltodextrin you are reducing your body’s capability to fuel itself. Instead, you are shifting the burden away from fat metabolism towards carbohydrate ingestion. You’ll be at the mercy of aid stations.

      All this said, when you are competing, you go all in. You use everything to your advantage—including fuels.

      • Eric says:

        Hi Ivan,

        Thank you so much for taking time to reply. I actually came to a similar conclusion as yours : during training, have my long runs without fuel, in order to improve my fat metabolism. During races, have them to go faster!
        As for my low-level aerobic base, I don’t quite understand what you mean by ‘speed up at the beggining’… I’m not sure at all that my aerobic base is solid.The times you see are /km not miles. That’d make me run at about 10min/mi which is rather slow, don’t you think ?


        • Eric:

          Yes. The way that I said it was very confusing. I should have said “the reason you pick up speed”. For example, when I started running at MAF, my pace was 9:20 minute miles. However, an hour into my run, I would start speeding up at the same heart rate, hitting 8:30 minute miles. I asked Dr. Maffetone about it, and he told me that it was my low-level aerobic base—the one that is responsible for the basic upkeep of my body and my energy levels, was very well developed. Even though I wasn’t achieving superior, i.e. athletic levels of speed, just the fact that my speed (whatever it starts out as) rises over time instead of dropping means that there’s actually a lot of well-developed aerobic machinery hidden inside my body, that isn’t as accessible as the aerobic (type I fibers in the muscles) and therefore takes longer to rev up.

          To use a metaphor, even though your aerobic base isn’t powerful (think of this as being the Y-axis on a graph), it is extensive (think of this as the X-axis). You don’t go very fast (yet) but the athletic output you do achieve, you can produce for a while. Because your aerobic base can do that, then it doesn’t have to rely very much on the anaerobic system when you’re talking about low or moderate efforts, such as working, moving around, yardwork, etc. Long story short, a greater percentage of aerobic function across time equals more health.

          I hope I’ve explained myself better. Please don’t hesitate to ask for further clarification.

  • Jason M says:

    Hello Ivan,

    I need a MAF reset.

    At the recommendation of a physical therapist friend of mine I started MAF training after recovering from an over training issue a few years ago. I ran 6 months with the 5 beats below max MAF which was 140 for me at the time. Once I got healthy and got into winter time I raised the max back up to 140. I continued to take the tests monthly but basically plateaued. I was not sure if improvement were due to the training or the weather cooling off here in Florida. I kept at it for another year and did not see any improvements. At the start of this summer I turned the alarm off on the garmin because I wanted to go out and run and enjoy it and not have the constant beep. Although I kept tracking the activities

    I have listened to the podcasts with Dr Phil on Trail Runner Nation, Robb Wolf and just discovered the new ones on Endurance Planet. Having said that I really think this approach is the right way and want to do a reset of sorts and see if I can get back on track. Here are some particulars.

    – 42 years old
    – Run 3 times a week, 50 to 70 minutes.
    – Resistance train 2 times a week using body weight exercises, pull-ups, push-ups, squats, etc
    – Paleo diet and generally pretty low carb with the exception of dark chocolate daily and some red wine on the weekends
    – Resting heart rate is pretty high. 60 to 70. This has been the case since I was a kid.

    Here are my thoughts based on the article above and reading the comments. I enjoyed Ian’s BTW.
    – My warm up and cool down probably sucked. In fact based on the 10 minute as 20 to 25 beats below MAF they did for sure.
    – I may need to add in a couple more days running based on your comment above. 5 days for 60 minutes.

    What do you think I am missing? I am not looking for an excuse to run above MAF. I do one half marathon a year but I don’t really race competitively or anything so there is no ego to worry about.

    • Jason:

      Use the MAF test. It doesn’t just tell you whether you’ve been improving or not. It tells you this: if you haven’t been improving, there’s some bottleneck to your aerobic development. Stress—any kind of it—increases anaerobic output. If you’re stressed at work or in life, even a slow run at your MAF heart rate may be anaerobic. Don’t get me wrong—the MAF heart rate should be aerobic. But when it isn’t, there’s some stressor that just isn’t letting your body kick in. Do an inventory: previous injuries? Medical conditions (particularly cardiovascular or metabolic)? Muscle imbalances? Work stress? Life stress (bad relationships, the death of a relative, etc.)? Any one of these things could be contributing to your plateau.

      Adding more days of strictly MAF running is a good idea. However, if you get to 5 days a week, make sure that you rest for 2 consecutive days. When developing the aerobic base it pays off more to be conservative than liberal. Incidentally, how fast are you?

  • Jason M says:

    One addition. I live in Florida. It is hot and humid. I try to run at night during the summer but the heat has a dramatic affect on my pace/MAF as much as 1.5 minutes per mile.

    • Jason:

      That’s ok. Distance running is more of a metabolic challenge than a muscular one. The heat is challenging your metabolism. Even though you’re running slower, your metabolic ability to run (which is really what matters) is still developing. At some point, of course, your muscles will need to catch up, but that’s what the winter is for 🙂

  • Jason M says:

    Ivan, thank you firstly.

    Following up on your question. I was always more of a sprinter than distance runner. There was a point where I ran a 5:10 mile relatively easily but that was long ago. Recently my half marathon pace was 8:50. My MAF speed right now is 12:15 during the day. At night time that pace is much faster sometime down to 10:15. So you can understand the frustration a bit. When I got injured/over trained a couple years ago we had just had our second child so there was stress from lack of sleep. That was when I started MAF training. The great thing about MAF training is that I rarely am tired after I run. The old saying is definitely true where I feel that I could go do it again.

    Thank you again. It is nice to get feed back because there are very few people that are versed in MAF.

    • Jason:

      I understand. I ran 17:25 5Ks myself in college.

      I think that the ways in which we’ve been taught by the establishment to think of training is quite counterproductive. We think that particular exercises train “strength,” “speed,” or even VO2 Max. And while they certainly help increase those measurements, training doesn’t really work that way. For example, strength is mostly a measure of the neurological output that the brain can put into the muscles. However, it also requires coordination, bone mass, and fascial strength. If you train coordination (or any other of a number of things), your expression of strength goes up. Your expression of endurance goes up.

      What I’m trying to point out is that there is a big difference between training speed and expressing speed. Sure, you may not be expressing the same speed while you’re training at your MAF heart rate, but you’re training one of the most fundamental underpinnings of speed (yes, and also of endurance), which you can’t train as reliably with other forms of training. In other words, instead of classifying my into “strength,” “speed,” or “endurance,” I classify them in terms of what subsystem I’m developing. When I’m jumping rope, for example, I’m training the coordination of foot pronation/supination with the internal/external rotation of my hip/leg system in a triple flexion and extension paradigm: in other words, I’m fine-tuning a gait-related motor pattern. When I’m doing heavy barbell exercises, I’m training the magnitude of my neurological output. And when I’m training MAF, I’m developing the breadth of my aerobic base, in particular my ability to buffer lactate.

      By thinking of exercises in that way, it’s a lot easier to justify MAF training to myself in the context of athletic training, and to use it more effectively in the process of developing speed, power, and endurance. That’s how I talk to myself about it, and it’s shown me this: when someone passes me by, I realize that I’ve been running 7 or 10 miles, but they’re maybe only at mile 2. And when I look a little harder, I see the strain etched on their face, or some power leak that their body can’t afford to correct because they’re under too much stress. And I see the contrast in myself, and i get reminded of where I’d rather be.

  • Jason M says:


    Thanks again. Please don’t take my questions as doubting the MAF method. I am inquisitive by nature. Second, if I am going to do something I want to make sure I am maximizing the effectiveness. I want to be more efficient. Frankly I enjoy the fact that after a run I am not spent. Competition is not my end result, health and enjoyment are.

    Two follow ups. How would you interleave strength training into the MAF training? Should I do it on off days or leave two whole days to rest only?

    • Jason:

      It depends. If you’ve been injured or overtrained (or if you are recovering from injury or overtraining) then stick to 100% MAF training. But if you aren’t, 80% of your total training volume should be aerobic (at MAF), and 20% can be anaerobic. Typically, most people should leave 1-2 days to rest. So, if you train 5 days maybe you can do 4 aerobic and 1 anaerobic. Your choice.

      Remember, your body doesn’t actually develop by exercising. It develops by resting. Too much exercise and too little rest and you compromise your training goals.

  • JT says:

    Have been loving the Maffetone Method.

    Question though regarding nutrition during mountain bike cross country racing. I am an age group MTB national champion and as of yet haven’t done a MTB race while doing the Maffetone Method (coming into season soon). Typically the races last 1:15 – 1:30 hours. Is it ok to still use gels during the races or what else would you recommend?

    Appreciate your help.

    • JT:

      Gels are great, but start ingesting them 20-30 minutes into the race, once your aerobic system is going hard. Alternately, you can also use a solid food such as Phil’s Bars an hour before beginning, which would mean that the food hits your small intestine just as the race starts, meaning that you’ll be taking in those calories for the majority of the race. Another option is to make a Phil’s Shake that you drink say half an hour before the race

  • kingsley says:

    Hi, I really enjoyed the article and the comments, particularly the Ivan/Ian dialogue. My Question is, I am about to start running more and have not (yet) got my HRM. I do practice nasal breathing (only) as I run presently and from the sound of what Ian was saying this alone might approximate an aerobic threshold. It will be interesting to see where my HR is at when I am at the point that I cannot nasal breath solely for an extended period, and need to open my mouth. Any comments? Would the need to mouth breath correspond with the MAF formula HR?

    • Kingsley:

      Personally, I don’t think so—or at least I don’t think that can be applied as a rule. If I try hard enough (and it is hard) I can breathe exclusively through my nose at 175 BPM, just above my lactate threshold. Generally speaking, I’d bet that you’ll find that the MAF HR is well below the nose/mouth breathing threshold.

  • FergC says:

    Hi Ivan,

    Just a quick query on my MAF pace. I performed the MAF test yesterday (four miles on a track after a 15 minute warm up) and the average pace for the test period was 7:32 minutes per mile. My aerobic HR is 148 (I have been running for 6 years but did not make any adjustments to the max HR as I was injured for 3 months this year).

    After reading so much about the method prior to undertaking the test I was expecting a slower average pace. I focus mainly on ultras but have done shorter races (5k pb 17:31, 10k 36:28, marathon 2:59). What does this indicate to you?

    Don’t get me wrong, I am happy that its a fast pace but is there much scope for improvement if my starting point is 7:32?

    Thanks for any input you many have!

    • FergC:

      Good for you. It means that you have a very developed aerobic system. I think there is a lot of scope for improvement. What is your perceived exertion at MAF pace: on a scale of 1-10, 1 being walking around and 10 being trying to lift an SUV, how much exertion would you describe MAF pace as?

      • FergC says:

        Thanks Ivan. I was comfortable throughout the test. I’m in marathon training right now so doing 10k pace intervals and tempo intervals regularly (I plan on going full maffetone after the marathon to build a base over the winter). So compared to those runs I would say the MAF test was a 5 on a scale of 1-10

        • Good stuff. As I suspect, you have a pretty well-developed aerobic base, relative to your total power. To make a long story short, your heart rate at a given speed (MAF pace) tells you how powerful your metabolism is, while your perceived exertion (PE) at a given speed tells you how strong your muscles are. So, HR is a measure of relative metabolic power, while perceived exertion is a measure of relative muscle power (in both cases, relative to the total athletic demand).

          Generally speaking, I think you can improve a lot with MAF training—all runners can. Since you don’t seem to be injured or overtrained, I included a few guidelines and explanations below on how to best incorporate MAF to the rest of your training.

          For some people, particularly ultrarunners or full iron triathletes, their PE tends to be a lot higher at their MAF heart rate—it could be 6 or 7. That’s because their aerobic system is very powerful relative to their total muscle power. So, if their muscles can put out a total of (say) 10 joules, their metabolism may be feeding them the energy necessary to put out 6 or 7 joules at any given time (while in this metaphor, your muscles can put out 10 joules and your aerobic system can only feed them 5).

          What I typically do for endurance athletes, provided that they are not overtrained, ill, injured, or recovering from any of the three, is to alternate speed/power and endurance mesocycles: I use two-week mesocycles because that’s the duration of the body’s protein cycle (the body can only be synthesizing proteins at a high level for 2 weeks). So, what I do for the 2 speed/power weeks is prescribe 25-30% anaerobic or threshold training (this could be tempo, various intervals, or weightlifting), and 60-75% MAF training. For the two endurance weeks, I do 5-10% speed/power training (I like training race pace here with a bit of weights) and 90-95% MAF training.

          So, during the speed/power cycle I increase muscle power to bring up speed and bring down PE at MAF. During the endurance cycle I develop aerobic power and bring up MAF speed, and therefore increase PE at MAF.

          One of the reasons I like to stagger training like this is that in order to stay at an aerobic heart rate you need to be relatively free of stressors, even psychological ones. Getting startled by a car is usually enough to kick up your heart rate (your body thinks it’s a tiger and it’s mobilizing its anaerobic engine to get ready to flee). In the same way, a psychological stressor during MAF training, like very high PE (7-8 on a scale of 10), tends to be enough to stress your body out so that it naturally tries to switch over to anaerobic channels to prepare to flee or fight.

          So that’s a really good time to switch over and give strength and power a little more emphasis: in order to open up room for improvement at your MAF speed you need to bring down PE at MAF. Once you cycle back to near-total MAF training, you’ll be able to develop much more swiftly.

          • FergC says:

            Hi Ivan,

            Thank you for your reply. Thats very helpful. I was planning on adding some body weight exercises to my training when I start full Maffetone training (pistol squats, wall sits etc). But I like the way you have it split into two week chunks, thats something I would not have considered.

            A couple of questions:
            Do you think I should start training like this as soon as my marathon training is finished? Or do you think a period (say, a month) of just aerobic training before moving into the more advanced bi-weekly mesocycles would be beneficial?

            Do you have a suggested HR range for the intervals/tempos? Or is any running over my aerobic HR enough of a training stimulus?

            Many thanks for the insights, its been very helpful and I’m really looking forward to getting out training and putting this to the test!

          • FergC:

            I would say rest for a couple of days (calisthenics is OK here) and then start with the endurance mesocycle and then see if you’re ready to move on to strength.

            What I usually do for HR for speed training is first figure out my race HR. For example, my marathon race HR should typically be 10-15 BPM above MAF (although personal experience may give you a different answer). What I usually do for my tempo runs is run half the race distance at 5-10 BPM above race pace (whatever the race you are training for). Interval training I usually come from the opposite direction: for 100m intervals i want to be close to my MAX HR, and for longer intervals (say 400m) I might be running at 185-190 (which is 17 BPM below my own personal MAX HR).

            The big question to ask for choosing particular intervals is what energy system (and more specifically, which capability of that energy system) you want to train. A bit of LT training is good for marathon and the half marathon, but if you’re planning on racing a 10-K, you want to spend comparatively more of your anaerobic training volume training 0-5 BPM above LT, I’d say by doing mile repeats. (You’re still doing the same overall percentage of anaerobic volume, just at a higher heart rate).

            For an ultramarathon, your tempo runs would probably be at marathon HR.

  • I use the MAF formula and MAF Test with all of my athletes. I am inspired by the improvements that my athletes make. I appreciate the work that Dr. Maffetone has done to educate trainers/coaches like me to help safely train athletes.

  • Warren Post says:

    Hello Ivan,

    I’ve recently recovered from a major illness. While recovering, I used the recommended formula of 180 – age -10 = 116. I believe that I have recovered, so I’ve adjusted per the recommendations to 180 – age – 5 = 121 (because I’m returning to exercise after years of layoff). To my surprise, my time didn’t decrease despite riding at a HR of five beats higher. Might this indicate that I am in fact not yet recovered from my illness and I should return to using 116?

    The details: I am 54. I was a competitive cyclist as a teenager but dropped it and all exercise until I returned to cycling a few months ago. I was making progress and even placed podium in my age group once until I was hospitalized with dengue fever in July. While convalescing I discovered the 180 Formula and applied it as soon as my physician allowed me to return to exercise, using a MAF HR of 116 as calculated above. In one month I improved my MAF test time by 10%, and felt so much better both on and off the bike that I decided that I am recovered from my illness and so should use a MAF HR of 121, again as calculated above. I repeated the MAF test at 121 four days after my last MAF test at 116, and was surprised that my time did not decrease despite the HR change.

    How should I interpret this surprising result, and what should I do henceforth? Perhaps I am not fully recovered from my illness and should return to a MAF HR of 116?

    • Warren:

      I’d say so. For example, I have a nagging muscle imbalance in my hips (which means that it’s serious for a runner). I take of 5 beats per minute because of it, even though I’ve been training consistently and increasing my speed for a few months now. But as soon as I go 3 or 4 beats per minute beyond my current MAF, I can feel my stress level noticeably rise, I can feel my heart in my chest, and I start breathing noticeably harder. Everything is telling me that my MAF is what it currently is.

      A 5 BPM increase that is not aerobic won’t increase your aerobic speed, but it’s also small enough that it doesn’t create a lot of anaerobic activation. It’s a lot more important to stay where you’re comfortable. Training 3, 5, or 7 BPM below MAF isn’t going to substantially change your aerobic development, but going a few BPM above MAF may hurt it. The problem is that the added stress tends to reduce aerobic function.

      You have very little to lose and everything to gain by playing the long game.

  • Jonathan says:

    The comment above about metabolic/muscular power and how perceived effort at MAF changes as you base build is very interesting. After 3 months of base building, I think this might actually be starting to happen to me now.
    When I started, it was hard to keep my heart rate down, even though it felt like my perceived effort was 3/10. I remember thinking this isn’t intense enough, so often times because going so slow affected my running form, I would “allow” (cheat) myself to go up to occasionally go up to MAF+5bpm, but no more.
    3 months later, it’s starting to become the other way around. If I take it really easy, I find my HR dropping below MAF by up to 3 beats, especially on small downhill sections! I’d say my perceived effort is now around a 5/10 at MAF HR. In my mind now, it’d be a lot more work / “effort” to go at MAF+5bpm, so I wouldn’t even want to “cheat” anymore! In another month or so, I might even be complaining that MAF is too intense!!


    After listening to some ultra/MAF related podcasts on a website called “enduranceplanet”, I decided to do a 10 mile MAF test today (which I heard Phil talk about). I used a 10 mile loop, not perfect but not bad either.

    Technically I used the first few miles to warm up (HR lagged like it does, but gradually increased to my MAF HR after 3-4 miles). I think this is okay though, because the past few months I’ve become accustomed to how this HR generally feels, so I knew how to start and build into it.

    Here are the mile splits/HRs (I’m 22 years old, so MAF HR = 158bpm):
    8:11 @ 136
    8:23 @ 151
    8:17 @ 156
    8:23 @ 159
    8:21 @ 159
    8:15 @ 157 (flat country road)
    8:15 @ 157 (flat country road)
    8:23 @ 157
    8:16 @ 159
    Average: 8:19

    Whilst this is a massive improvement on the end of June (23min 5km) and the end of August (8:5x-9:0x and 21:33 5km), I’d love to take it into the 7:xx range in the future.

    What’s interesting is that I no longer positive split / drop off. In fact, I feel like I could do this for 3+ hours and still not drop off. I even noticed my HR drop to 157bpm on miles #7 and #8, whilst my perceived effort decreased as I settled into it (perhaps a lack of warmup). It felt super light.

    Since the MAF charts put a 8:00 MAF @ 20:12 for 5km and a 8:30 MAF @ 20:58 for 5km, I guess my current 5K would be in the 20:3X range? This is good news. I’d love to run a sub 20 5km though, so my MAF pace isn’t quite there yet. I have a feeling I may be able to perform slightly better than the MAF tables indicate though, because of my natural speed/anaerobic qualities. I plan to do a 5km race some time next month!

  • Michael Ryan says:


    Tried the MAF test tonight, Just wondering should I have warmed up more at first did about 15 min but test times went down instead of up. found it really difficult to run this slow kept speeding up and slowing down to a walk for first mile, I think this skewed results a bit. Not really looking forward to 3 months training at this pace, but will try, hoping for the best. results below of test below. My 5k time is about 24min and marathon about 4:20 is this sign my aerobic system is not great, compared to results below.
    Mile 1 16:02
    Mile 2 15:48
    Mile 3 15:33

    • Michael:

      Thanks for your comment. Yes, your marathon times, 5k time, and MAF pace do match up (although this isn’t an exact science). But let me give you a different way to think about MAF training altogether:

      MAF training means that you’re training a different “gear” (like the gears of a car) than you usually do—a “gear” that lets you use energy almost limitlessly, and drastically increases the distance you can run (and the speed at which you can run it). The MAF HR isn’t the speed at which you run your marathon, or your 5k, or your 100 yard dash. It’s the heart rate at which you can best train that fat-burning gear. So, what I would do is stop comparing MAF pace with any other pace, and focus on increasing MAF speed from one month to the next.

      My recommendation to you is to jump in with both feet. Remove stressors, increase your aerobic function, train at the MAF pace, and watch your aerobic system grow.

  • Luke says:

    Ivan, thanks for taking the time to really contribute to the information on this website.

    In response to the inevitable questions about the 180-age formula you assert high correlation with clinical tests. But does this apply to the average population or the individual? In other words, what is the standard deviation? Something could have great correlation but still predict it incorrectly for an individual by 5-10 bpm, which is significant.

    If, regardless if your response, I chose to clinically measure metabolic efficiency (through a respiratory exchange ratio test) what is the %fat burning that best correlates to the training advice described on this site? As previously discussed it would clearly not be 100%.

    • Luke:

      the ratio you’re looking for is .87 or RER. The 180-formula is certainly not completely accurate (I don’t know the standard deviation) but I do know that it plays conservatively. It may indeed predict incorrectly for an individual, but for example, it is accurate down to the beat for me. I believe this to be the case for the overwhelming majority of people, particularly because it allows people to adjust based on their own perception of what category they fall into.

      (So, in a way, that may help normalize much of the variation).

      As time and resources allow, we plan to do much more research on the 180-Formula.

  • […] consegui uma grande redução no pace médio neste período, mas quero confirmar pelo menos três testes MAF antes de sair cantando […]

  • Amir says:

    Dear Ivan,

    I’m a late bloomer, and started regular training just a year ago after a sedentary life (I’m nearly 59 now).
    I was presented with the MAF method, got persuaded, and I’m doing it for the last 4+ months, with much enthusiasm.
    Set my MAF HR to 112 (220-58-10 due to medications), train 5 days a week (15+30+15), alternating between walking on treadmill @ cross-trainer at the gym, and abandoning all my force (anaerobic) sessions.
    Worth mentioning that I usually push to the upper limit of my MAF HR zone, exceeding it just slightly only by up to nearly 2 minutes overall.
    My personal feeling is great, I feel fresh and energetic after each session, and I live excellent with the “easy pace”.

    However, I’m confused with my MAF tests results. Did already 3 of them (@ HR target of 105), and it seems that I’m stuck in a plateaux, or even worse:

    August October November
    Km 1 9:43@106 10:30@105 10:48@106
    Km 2 9:50@105 10:12@106 10:49@106
    Km 3 10:03@105 10:16@107 10:38@107
    Km 4 10:06@105 10:12@106 11:22@107
    Km 5 10:06@105 10:24@107 11:09@105

    I’m aware of the variance between different machines at the gym, but I can’t see any progress even through my regular trainings (not exceeding more distance at the same time frame).

    Should I just give it more time, and look forward for improvement in the upcoming months?
    Should I lower my MAF HR more? If so – by how much?
    Some other suggestions?

    • Amir:

      Over the winter, a lot of people see their speed decrease due to the body’s long-term cycles: we’re wired to slow down during the winter, so your losses in speed may be a reflection of this. However, I wouldn’t bet on that. Some of the main reasons people see their speed decrease is because either the amount of exercise means too much stress (probably not your case), or because some other stressors (lifestyle, nutrition, etc.) that are either impairing aerobic function or reducing your body’s ability to adapt. When aerobic function is impaired, your aerobic system becomes less “trainable” by aerobic exercise.

      As you can see, there’s a lot of possible factors contributing to the loss in speed.

      But given that you’re coming out of a sedentary lifestyle, I’ll tell you this: your ability to recover and build your body from more intense training is a faculty of your aerobic base. While strength training does cause people to put on muscle and bone mass relatively more quickly, it’s very easy for that kind of training to become stressful enough that the body stops recovering. So, a year or so of aerobic training can do a lot for your ability to expand your training in the future.

      For example, in my case, I went from 5:49/km to 5:20/km from July to September, and right now I’m “back” to 5:49/km. I’d love to see steady-state training improvements, but the body’s cycles oscillate with the seasons, and winter is the valley (not the peak) of those oscillations. I’d expect that running MAF through the winter would yield a speed quite faster than 5:49/km.

  • Amir says:

    Regarding my last question – of course I meant 180 and not 220!

  • Pieter Smith says:

    Thanks for this great article. I do have some questions that I was hoping you might help me answer, but overall I am enthusiastically in support of the basic philosophy of this training method. Ok, so on to the questions. My understanding is that at any one moment in time, when you are exercising both your aerobic and anaerobic systems are engaged, although the proportions vary based on exercise intensity. Your anaerobic system (glycolysis) produces pyruvate which quickly gets turned into lactate (unless it is immediately used by the aerobic system, see below). The anaerobic pathway (glycolysis) also produces H+ (technically, H3O+), acidifying muscles. The aerobic system is much more efficient and can take fatty acids from fats (entering as acetyl-CoA), carbohydrates, or pyruvate (which can be obtained by conversion of lactate) as fuel. Ok, so now that I’ve laid down how I understand aerobic/anaerobic metabolism (please correct me if I’m wrong), I will get to my question. Fundamentally, it seems that the point at which you switch from generating energy, say 95% aerobically to 94% aerobically (or whatever is the cutoff for the MAF test would be) is a factor dictated by the chemistry that happens inside the muscle tissue itself. It seems it would only be influenced by the heart insofar as the heart’s fitness to some degree influences the availability of oxygen to the muscle tissue. Given this consideration, it seems that if you were to do a lab test (the 4 mmol lactate threshold test), the results of that test would give you a more accurate picture of what your heart rate is when you switch from being “aerobic” to being “anaerobic” than the 180-age formula, isn’t that correct? What I am saying is that the MAF test heart rate might give you a very good guess at which point you switch from “aerobic” to “anaerobic”, but if you did a lab test, could you narrow that point further?

    • Pieter:

      Muscle metabolism and heart rate are inextricably linked by the hormonal system on a very deep systemic level, particularly the HPA (Hypothalamic-pituitary-adrenal) axis. If you increase the stress hormones in the body, you also get an uptick in insulin: more sugar enters the cells from the bloodstream, which means that the amount of available sugar can easily exceed the amount of available oxygen (creating anaerobic function). But an increase in stress hormones also means (1) that you increase the “hunger” hormone ghrelin, which, along with insulin, reduce the “fat-burning” hormone leptin, and (2) that you increase SNS activity, which increases the heart rate.

      So, given these deep-level links between the heart rate and the metabolism, you’re not really going to be able to produce a situation where, past a certain threshold you can get an increase in heart rate (due to stress hormones and SNS activity) but no increase in anaerobic activity.

      And since the link between oxidative and non-oxidative pathways, and heart rate is mediated by hormone levels, aerobic function isn’t really going to be mediated by cardiovascular fitness: the hormonal changes that result in a reduction of oxidation and increase in anaerobic function occur at a very high heart rate reserve (long, long before your cardiovascular fitness maxes out).

      Incidentally, the only situations where people’s oxidative ability is mediated by cardiovascular fitness is when they have a very low MAX HR due to congenital or acquired health issues. And the reason this happens is because cardiovascular fitness maxes out before, or close enough to, the point where hormonal chemistry enables the change from oxidative to non-oxidative pathways. In other words, these people can’t express very much power, not because they don’t have good anaerobic channels (they may or may not have them), but because their (lack of) cardiovascular fitness stops them from expressing it.

      The best lab test that you can do in order to figure out aerobic and anaerobic function is a respiratory quotient (RQ) test. Usually, an RQ of .87 corresponds to the MAF HR. Why this is the case goes back to the initial question: aerobic function is a systemic, not local, event.

      If you have a muscle in a lab, you can’t really stimulate it to produce a lot of oxidation, because the Acetyl-CoA necessary for oxidation will run out very very quickly, soon after the glucose that powers glycolysis runs out. Once you have Acetyl-CoA, in order to create oxidation you need to minimally provide (1) oxygen, but to keep it going for any significant period of time, you need to (2) start breaking down fatty acids to get Acetyl-CoA. So, while you can locally provide the fuels to create oxidation, you need the entire system to keep it going for any useful amount of time.

      The reason that RQ is so important, then, is because it tells you the systemic use of oxygen. If you were going to test muscles, you’d need to test each and every muscle in the body, which is (1) not only untenable, but also (2) only tells you which muscles are working oxidatively in the setting that you test it. If you go from a treadmill onto a bike, or from the bike onto the road (or onto the trail), you are going to find that the rates at which you are using oxidative vs. non-oxidative pathways in particular muscles are (1) different from the test setting, and (2) fluctuating in different ways.

      But, since the RQ test looks at a systemic indicator of oxidation (ratio of 02 uptake to CO2 output) and pairs it with another systemic indicator of metabolic function (the heart rate), you can pair these two indicators to generalize oxidative function: HR @ .87 RQ is your aerobic threshold.

  • Pieter Smith says:

    Thank you. That answers my questions well.

  • David says:


    I’m a recreational runner. I’ve been running for 2 years. I tried MAF around 6 months after starting running as I was plagued by injuries. I didn’t stick with it. I found it difficult to run at such a slow pace and I had my first marathon that year. I felt it was taking too long and I wasn’t getting anywhere.

    Well, 18 months on and 4 marathons later I’m still plagued by injuries. My times have improved and I am a better runner than I was but I am constantly getting injured. I have a place in the London marathon next year and I feel I’m at the stage where I want/need to give MAF another go. What I’d like to know is, does it work for slow runners? My fastest marathon time is 4:26. My half marathon PB is 1:54. I’m not a hugely quick runner. I’ve read about all the people having success with MAF but they all seem to be fairly accomplished runners/athletes. What about the average person?



    • David:

      Let me put it to you this way: your marathon performance depends on your ability to burn fats, regardless of your degree of competence. Essentially, that is what the MAF method does. That said, less competent athletes can often attribute their lack of relative competence to a relative lack of running skill base. I’d recommend lots of skill work to quicken your progress.

      • Terry says:

        David — when I read your comment, it could have been written by me (with a few exceptions). I just learned about this MAF method this week, so I’ve been doing a lot of reading. I’ve been running for a few years longer than you (about 4-5), used to get injured, but not any more, and my marathon PR is 4:32, 1/2 marathon PR is 1:58. I consider myself a ‘slow’ runner as well, but I’m looking for ways to improve my speed, not a lot, I’m in it for recreation and health, but would like to continue to see some incremental improvements.

        I’ve done 6 marathons now in the last 3 years, and all of my results have been within 15 min of each other. I’ve been tracking my HR almost since the beginning of my running career, but never really trained by HR nor thought much about it, I mostly run by feel by admittedly, focus on pace (too much). I looked at my last 100 runs or so going back to May of this year (my last marathon was in October) and I discovered that I’ve been training about 10% of my runs at the MAF method HR, and 90% above. According to what I’ve read about this method so far, that needs to be flipped.

        My next marathon is in June 2016, I’m going to give MAF ago this training cycle and see what kind of improvements it can bring.

        Just keep running!

  • Trent says:

    I have the opposite problem that most people have with running at MAF. I’m 26 years old and when I run at ~150 HR I feel like I’m going a lot faster than I can sustain for a long period. My 10k pace is usually around 6:30 min/mile and when I’m running at 150 bpm, I’m at 7:30 pace or even faster sometimes. This seems to fast in comparison to my race times to be an aerobic pace for me. I’ve had a few injuries in the last couple years, so I’ve been taking 5 beats off of my MAF and keep it at 150 when I’m trying to run at MAF.

    Any thoughts on why MAF seems so hard and fast for me or changes I should make?

    • Trent:

      Basically, it’s because you have a very powerful aerobic system, relative to your maximum muscle power. “Effort” is how much of our maximum muscle power we’re using: a weekend warrior and an olympic weightlifter are feeling the same “effort” when they do their 1RM (1 repetition maximum), but of course, the olympic weightlifter can produce lots more power at that same effort.

      So, the way to reduce effort is to increase your maximum muscle power, so that your aerobic system becomes slightly less powerful relative to your maximum muscle power. How to do this? Integrate a healthy amount of strength and speed training into your routine (I’d say 15-20% of your total training volume).

      What I would do is to train strength/speed at that percentage for 2 weeks, and then go back to mostly MAF for the next two weeks, in order for your aerobic system to “catch up,” and so on and so on.

  • Naz says:

    I know that running at a lower HR a.k.a easy/slow pace prevent us from getting tired the next day, increase the build-up of mitochondria and prevent injury. Running at a slow pace after a long time will get bored easily.
    With no introduction to speed such as intervals and sprinting, how are we going to improve our performance in this case? Does VO2 max plays as special role in this? In a given week, when can you add intervals, long run and easy run? For me, I would like to improve my time.
    I will get cramped calves when I race but not during training usually occur at mile 10. I don’t know why. Should I add more mileage? Some say that when you turn 40 above, your organs start to decrease.

    • Naz:

      Running at a lower (aerobic) heart rate will improve your time. Keep in mind that for aerobically-developed athletes, running at an aerobic heart rate typically means running fast and at quite a bit of effort. So, it’s not “running slow” that we’re selling here, per se. What we’re selling is the idea that the overwhelming majority of your training, you should run at a heart rate that improves your aerobic base.

      The aerobic base is essentially the mechanism that allows the body to produce energy for a long time, by combining two near-limitless fuels: oxygen (from the outside) and fats (from the inside). For this reason, (1) performance in any sport that requires us to function for over 1 minute necessitates an important use of the aerobic base, and (2) performance in any sport that requires us to function for over 5 minutes is overwhelmingly due to the power of or aerobic base.

      Unless you are a sprinter or a weightlifter, working on diligently developing your aerobic base is the only way that you can expect to continue making performance gains in the long-term. And even if you are a sprinter or a weightlifter, it is important to develop the aerobic base in order to be able to recover well from your workouts.

      The interplay of VO2 max into all this isn’t really something you should worry about, unless you are trying to bring your marathon time down to 2h25min from 2h30min. In other words, just about everyone has the genetic qualities to be able to run a hell of a marathon, if they were to train optimally.

      If you aren’t ill, injured, or overtrained, and training isn’t stressing you out, then it’s quite alright to add one speed or strength session per week.

      It’s very difficult to answer the question about cramped calves for sure. However, one common reason for why it happens is because the heart is getting fatigued early in the race (because it has been beating too fast for too long), and more blood starts to pool in the lower leg. In other words, you’re running too hard for the distance you’re attempting.

      I’m sorry to say I can’t answer the question of adding more mileage. I’d need to not only know how much mileage you’re currently running, but to have a reasonably comprehensive understanding of your current health and fitness status. Unless I was your coach with a deep knowledge of your situation over a period of a few months, it’s not a question I can answer responsibly.

      That said, I hope I’ve answered all your other questions. Let me know if you have any more questions or you want any clarification.

  • William says:


    first of all your comments are a real improvement of this site! Thanks!

    my Maf score is 141 (my age 39)

    -little is written about Hr at race pace.

    Is the Hr at races just based on personal experience or could you give some insights on some benchmarks? Especially the longer events like an ironman, ultra run or long bike race?

    (Tests couple of years ago (before I started using Maf 🙂 ) showed I could maintain quite long a high lactate level))

    As an example: if I want to do a bike race of 180 km with some cols, can I climb at 170Hr if the PE feels hard but ok or do I hold it at max 160Hr b.e.

    another question:

    -sometimes during my Maf tests my heart rate goes very high, very suddenly (till 90% of my max Hr but fith a fairly normal PE) (my heart rate monitor measures correctly) > at that point I need to walk to get it low again (roughly 5 minutes, mostly performed in interval, because I try to run again as soon as possible) . usually after this period, the Maf test continues as normal, with normal PE – Maf Hr.

    I had an active live, but last two years I had to substantially decrease training due to work :-/ My Maf times are now the worst since I began to measure. Could the tempory swinging heart rates be a sign of a decreased aerobic system and if so what’s the explanation of this effect? Or is this a sign of something else (heart dysfunction,…)?

    Best regards and excuse me for my sloppy english

    • William:

      Check out this podcast with Dr. Maffetone on how to use heart rate to set race pace, particularly in the endurance races.

      Usually, those types of swings happen because something changed in real time. Usually, it happens because, say, we got excited about something. (For example, I often find that my heart rate has gone up 20-25 BPM when I start daydreaming about racing). What I’m sure is that we can’t know whether these changes are due to a heart dysfunction, although it’s unlikely that they are.

  • James says:


    I am 43 and used to be a road runner. At peak i ran a sub 4 hr London Marathon in 2010. Since then, due to children and having become disillusioned with road running I have only been running for 40 mins twice a week but have adopted minimal/barefoot and now follow a high fat low carb/Paleo diet. I am still trying to work out which is best. For example Tim Noakes eats perhaps once or twice a day and will eat sausages whereas PM recommends smaller meals more often for optimal fat burning. I have generally been following HFLC and within a couple of months by belly fat has disappeared and i eat twice a day with an avocado for lunch.

    I want to run a half marathon trail race in July but am unsure what training plan to follow and if 6 months is enough preparation? I have no idea how fit or fast I am.

    How long should i build a base for? (for the last month I have been using MAF and running 60 mins 2 or 3 times a week with an average of 138-140) but this is mainly on roads. The runs feel very easy and i’m sure i could run for 2 hours at a time.

    At what point can anaerobic sessions be included in order to prepare for trails and what form should they take If i can only manage to run 3 times per week?

    Thanks in advance.

    • James:

      You don’t need anaerobic sessions to prepare for trails. In fact, since trails are essentially tiny intervals, training aerobically in particular will prepare you for trails: you’ll recover from these “tiny intervals”—the uphills and downhills and jumps—much more readily.

      Furthermore, 98% of the energy you use to power a half marathon comes from the aerobic system. You don’t really need to include anaerobic sessions to prepare for a half marathon. On the other hand, if you are competent enough at that distance that you can easily finish it and are trying to increase the absolute speed at which you can run it, then 5-10% of your total training time could be devoted to anaerobic training. (In other words, to run a half marathon, you need the aerobic system. To race it, you need to develop power).

      I think that 6 months is a good bet for a half marathon, given that you used to be a road runner.

  • Sean says:

    I have found that high mileage works for me for base building does how do I maintain this amount of mileage (100 miles/week) during the season in order to achieve high performance at the end of the season versus the beginning of the season where I start off with a high amount of mileage and come in with pr’s left and right then the speed training that my high school coach wants us to do and I end up over training because I stop doing my normal mileage per week. Would you recommend that I maintain that mileage during the season in order to both deal with hard anaerobic workouts and over training?

    • Sean:

      That is an impossible question for me to answer. But you can answer it this way: go to your local track and do a MAF test. Every month, do another one, at the same conditions. If your speed at your MAF heart rate begins to drop, or plateaus for more than 2 tests, you are doing too much volume of some kind: perhaps your mileage is too high or perhaps your speed training is too much.

      In either case, you should begin to cut down on training (if it turns out you need to) by first reducing your speed training, and then if that is not enough, reducing your overall mileage.

  • Heather says:

    I’ve been research MAF because I had a pretty rough year health wise. I had a genetic test done that said I would be prone to soft tissue injuries and have been plagued with a high hamstring and sciatic issue for a couple of years. To top that off, working with two functional medicine doctors this past year on adrenal fatigue, mitochondrial dysfunction, blood sugar issues, hormone imbalances, unexplained weight gain. I promised them both after my summer racing season that I would take a couple of months off to rest. I did hold to my promise. It’s time to get back to training and this week I started with MAF (138). I will admit it has been extremely difficult, my average MAF pace is between 10:30-11:00, such a difference (about 3 minutes) from my normal “easy run” pace that I twisted an ankle the first day trying to see my HR monitor. With my health issues, I have to be grain free and therefore, am low carb and high fat for most of the past year. I am also a health coach so know that I have gotten rid of any food sensitivities that I might have possessed in my diet a year or more ago. In that same genetic test, I also learned that I am carb sensitive so this is a way of life for me always, not just for 2 weeks as the test suggests. I am also a fitness instructor so do have about 2-4 workouts (mostly weights) each week at the gym that my HR is well over my 138 MAF and even while I cycle (something I changed to this fall to help with the stress on my adrenals from running) takes me over that effort when I am not working very hard. My question is, and I haven’t seen anyone else post something similar, is that I have zero desire to go back to marathon or even half marathon training this year. My spring/summer running season is going to focus on the 5k and trying to break 20 minutes (my average 5k race time for the past couple of years is about 20:30. Since I am not interested in long distance endurance training this year and would be happy to keep my runs from 3-6 miles, does all of this still pertain? I am willing to work through the struggles of walk/jogging at a heartrate that is this low if there is benefit but if I need to work down to sub 6:30 race pace, is this the right place to start? It’s a lot of information to comprehend even if it makes sense but can be extremely frustrating at times with pace times I have never really run and a HR monitor that never stops beeping at me – yikes!

    • Heather:

      When people have recurring chronic injuries, it’s because their body isn’t quite able to recover. Essentially, aerobic training builds and develops the machinery necessary to recover, and in doing so makes the body more and more resilient to training. In other words, aerobic training is essential to everyone, particularly for people that want to see their speed increase (and not lose it to some future injury).

      Aerobic training pays off, and after a few months of it, you may find that it’s not “slow” training any more!

      • Marcello says:

        Hi Ivan,
        I’m from Italy and I read about this method on a forum. I’m 45 so based on the formula I’m using a MAF of 135.
        The strange thing is that after a warm up of 20 minutes at an average of 112 bpm and a pace of 9:10, I started to run at 135 bpm and my pace was the same; I decide to stop and go for a fast walk, result 130 bpm and pace of 8:05
        What does it means ? That my cardio/gps has gone or that I’m not aerobic

  • Marco says:

    Here are the results of my last MAF tests performed on the same track:

    January (cloudy):
    – Mile 1 10:23
    – Mile 2 10:43
    – Mile 3 11:18

    February (windy and rainy):
    – Mile 1 10:31
    – Mile 2 10:37
    – Mile 3 11:13

    I have a hard time analyzing them since the first mile in February in slower, however the second and third miles are faster. What conclusion can I draw from these data?

  • Doolah says:

    I have just begun using the MAF method because I would like to burn fat for fuel. I primarily lift heavy and do various HIIT workouts. Using the 180 – age my target heart rate range is 118-128. I trained on the recumbent bike and was very surprised at the effort required. I didn’t expect it to be challenging at all but found it to be a satisfying workout. I trained for 45 minutes (incl warm up & cool down), burned 720 calories and stayed in the zone for 35 minutes. Afterwards I immediately noticed that despite the intense workout (climbing entire time other than cool down) I did not experience muscle or joint soreness the way I do after doing interval training for an extended period on the elliptical or row machine. I am guessing this is because I did not build up the same amount of lactic acid because of the lowered heart rate target zone. Anyway, I am going to stick with this for a month and track if my distance output improves (7+ miles) and if my body fat % decreases. I appreciate any comments, suggestions.

  • Steven says:

    I just finished reading ” The Endurance Handbook” and liked it very much. I am looking for a bit of confirmation on my MAF target HR. I find it difficult to reconcile my theoretical MAF HR of 180-58= 122 with the average HR of the marathon I ran last weekend. My average HR was 168 for the race and quite stable, as was my speed throughout. A marathon is a 99(?)% aerobic affair and I therefore don’t understand why my MAF should be so much lower.
    I’ll do test to establish my RQ and see which HR corresponds to 0.87 to get more data but would be interested in a view on the above.

    • Steven:

      The 180-Formula is an estimate of your maximum rate (not maximum percentage) of fat-burning. It isn’t as accurate as say, a lab test that takes your RQ or RER. If you do a test, however, also look for Fat Max—i.e. the heart rate at which you are burning the most fats. For most people, it corresponds to an RQ of .85-.87, but it does vary.

      So it may be because of that. However, what that statistic—99%—means to point out is that the marathon should be a 99% aerobic affair due to the length and metabolic requirements. For most people, a marathon results in an unhealthy miasma of aerobic and anaerobic function. So, you can think of it this way: in order to be (yes, exhausted) but otherwise perfectly healthy at the end of a marathon it should be a 99% aerobic affair.

  • Simone Vannucci says:


    I have been following the MAF method and seeing the benefits in terms of stress reduction combined with a step up on my diet.
    Question is: what shape my aerobic system is in? The Formula is clear, the MAF test and principles are clear.

    I run 5k in 20:11 and my last MAF test was:
    KM1 5:13
    KM2 5:21
    KM3 5:24
    KM5 5-29
    KM5 5:37

    Is that a ratio between the MAF test and race time to assess the level of aerobic system development? I would like to know if I desperately need to work on my aerobic or not so bad.
    I am 42 @ 182cmx81kg


    • Simone:

      I’d say you’re doing better than 85% of the population at least. Generally speaking, highly-trained endurance athletes tend to race at a lower heart rate (but a much faster speed) than highly-trained endurance athletes. This is how race times correspond with a well-trained aerobic system:

      Table 3
      Average MAF Test vs. Running Race Pace (minutes per mile)

      MAF Pace / 5K Race Pace / 5K Time
      10:00 / 7:30 / 23:18
      9:00 / 7:00 / 21:45
      8:30 / 6:45 / 20:58
      8:00 / 6:30 / 20:12
      7:30 / 6:00 / 18:38
      7:00 / 5:30 / 17:05
      6:30 / 5:15 / 16:19
      6:00 / 5:00 / 15:32
      5:45 / 4:45 / 14:45
      5:30 / 4:30 / 13:59
      5:15 / 4:20 / 13:28

      (For reference, 20:11 corresponds to a MAF test of just over 8:30 minutes/mile (5:13 min/km). The chart expects that MAF test time to correspond to a 5k race time of 20:12). So you’re only a few seconds off at worst.

      This suggests that (provided you are healthy, with good energy, etc.) it’s a good idea to incorporate 10-20% anaerobic training into your schedule (80-90% remaining aerobic). That way, you’ll remain in good aerobic condition but still continue to develop strength.

  • Marco says:

    Today I ran my monthly MAF Test. However I was a few seconds slower on the 1st mile than on the 2nd one. Also I only felt warmed-up after the 1st mile. I warmed-up for 15 minutes but the temperature was 1°C. I guess next time I should warm-up a little bit longer?

    • Marco:

      It really depends. For example, out of a 10 mile run with 7 MAF miles (1.5 each for warm-up and cool-down), the last 3 miles of my 7 are usually the fastest. This is because my fat-burning keeps ramping up the longer I run.

      This is not to say that the temperature isn’t playing a role in you being slower the first miles. It most certainly is. But the real function of the “warm-up” isn’t to warm up per se, but actually to allow a period for your body to slowly and gently move blood out of your organs and into your muscles without having to force blood out and in (respectively) because it was surprised at the sudden onset of exercise. So, 15 minutes of warm-up is certainly enough to do that, even in very cold weather.

      But if, despite my answer, you still have the nagging feeling that it would be more useful to warm up for 1 more mile, then I’d say your intuitions are absolutely right, and there is still some more of warm-up to be done. However, i wouldn’t characterize this as needing to run that extra mile under the MAF HR: after 15 minutes, your body is 90% of the way warmed up in the most conservative scenario. What I’m getting at is that you’re not going to hurt it by running that mile at the MAF HR, and the worst you’ll have to put up with is a slightly slower MAF mile.

      Hope I’ve answered your question.

  • Pete says:

    Do you have a point of view on the “modified maf test” formula as described by the OFM folks? It I basically an alternative formula that they recommend for fat adapted athletes following their program. The difference between this is quite significant – (200-age and some bigger adjustments to the standard MAF formula.)

    • Pete:

      I answered your previous comment (check it out) but I want to reiterate this.

      I believe that being a “fat-adapted athlete” in the sense of OFM is an elite category. Quite simply, I would not use the modified MAF Formula. If I suspected that the 180-Formula was underestimating the aerobic threshold for someone, I’d recommend that they go get lab tested (more on this at bottom). Let me explain: We’ve found that the 180-Formula tends to underestimate the MAF HR of people with a very high VO2 Max (70+). Well, one of the biggest contributors to having a high VO2 Max is the percentage of Type I “slow-twitch” muscle fibers in the body. While this percentage can be influenced by training, how much it can be influenced and what percentage you start at is largely determined by genetics. This is important because Type I muscle fibers are the ones that burn fats.

      There’s another issue: since people have higher VO2 Max due to a higher percentage (not just a higher amount) of Type I muscle fibers, the aerobic threshold also occurs at a higher percentage of VO2 Max. So, you can say they are doubly blessed: Let’s suppose that for an athlete with a VO2 Max of 60, their aerobic threshold occurs at 60% of their VO2 Max, and for an athlete with a V02 Max of 70, their aerobic threshold occurs at 70% of their VO2 Max. So it also occurs at a much higher heart rate. (Also, this gives the athlete with a VO2 Max of 60 a maximum aerobic VO2 of 36, and the athlete with a VO2 Max of 70 an maximum aerobic VO2 of 49.)

      The 180-Formula works well for the “standard” person: someone who, when healthy, has a VO2 Max of 40-60. It lends the possibility to make adjustments as VO2 Max grows from training, but the adjustments this “standard” person has to make would never be as large as those suggested by the OFM formula.

      My suggestion is this: if you believe you fall into that elite category I described above, you’d do yourself a favor by going to a lab and get yourself analyzed. Figure out HR at:

      a) VO2 Max
      b) Fat Max (highest rate of fat-burning)
      c) Anaerobic (Lactate) threshold
      d) Aerobic threshold

      Your Fat Max should be just a few beats away from your aerobic threshold. The MAF HR (and 180-Formula) attempts to point at Fat Max for the average person. So, “Training MAF” is about training at your particular Fat Max for a majority of your training, so that your body has time to recuperate from racing, stress, and higher-intensity training.

      • pete says:

        Hi Ivan

        Thanks very much for your reply, and I apologise for the repeat question. When I “re asked” it I had not seen your previous reply, I am not sure if you had posted it. Thanks for a very clear answer. I am sticking with the original Maffefone method! Pete

  • Brad Patterson says:

    I just re-started Maffetone style training and nutrition about 4 weeks ago, and I just did my first MAF test this past Sunday. My HR target was 140, my mile splits were 11:03, 11:03, 11:08. My HR avgs for those mile splits were 140, 141, 141. I am wondering what it means that my pace did not drop off much in mile 2 or 3. I am sure that if I had done 2 or 3 miles more, the pace would have dropped off. But this result is a lot different from what I saw on successive mile splits when I was doing the Maffetone method about 5 years ago, so I’m not sure how to interpret it. Thanks!

  • Pepi says:

    After 2 marathon cycles following Hansons and Pfitz plans I decided to try MAF this time (marathon in late Sep.). I’m 52 so my MAF HR is 128 which I rounded up to 130, accounting for years of training etc. For reference, my resting HR is ~38bpm, and my HR max (as seen in a race) is only 158.

    It seems that everybody needs to slow down initially to keep their HR at MAF, but I’m quite the opposite.
    Running at MAF HR is not an “easy pace” for me – in fact it is faster than my marathon pace and feels “comfortably hard”.
    My MAF test splits (5miles) are: 7:34, 7:43, 7:49, 7:49, 7:50. During the first mile of the test I had to work harder than I wanted to in order to keep my HR at 130bpm.

    In comparison, my HM pace is 7:23 min/m (1:36:xx) @140bpm and my FM pace is 8:20 (3:38:xx) @135bpm. The races were 4 weeks apart, but while my HM was evenly paced, in FM I went out too fast, holding 8:0 until 36k and then faded badly.

    So, now I’m confused – what should I use as my MAF HR. Should I stick with 130 or set it lower? My “run all day” pace is around 9:00 min/mi @105-115 bpm

    • Pepi:

      You have quite a fast MAF pace so I’d say it’s possible you have an aerobic base that’s relatively powerful when compared to your total muscle power. Our perceived effort (PE) is tightly related to the amount of our maximum muscle strength we’re using. (Forcing open a jar lid and squatting 90% of your maximum take roughly the same effort because opening a jar lid requires 90% of our total hand power, while squatting that much takes 90% of our total body maximum).

      So the amount of energy that your aerobic metabolism can produce as fuel and the amount energy your muscles can contract with aren’t the same thing. Typically, the reason why MAF pace feels so easy for people is because their muscle contractile ability is so much greater than what their aerobic metabolism can produce. So, it’s very likely that your MAF is still that number, except that now you need to increase your muscle power accordingly.

      I’d say to pick a base-training heart rate of about 115 BPM while you develop some muscle strength (say, 1 anaerobic workout for every 4 or 5 slow workouts), and slowly move your base-training heart rate towards your MAF.

      • Pepi says:


        Thank you very much for your reply. You may have a point regarding the need to increase my leg muscle power. During hard runs, it’s never my heart or lungs that I have problems with, it’s always how much trashing and pounding my legs can take.

        I’ll try running MAF runs @110-115bpm with one anaerobic session per week, as you suggested.

  • Andrew says:

    Hi Ivan, I pushed a reply into the middle of the conversation about MAF HR adjustments for swimming, I haven’t seen anything back. I kept soaking up resources on the website in the meantime.

    I now believe you’ve addressed this, as I understand it it makes no difference if the environment or activity lowers or increases HR for a similar level of effort – the MAF HR stays constant.

    So even though my HR is generally lower when I swim compared to running my MAF HR is not changed, it just means I can push a little harder in the pool and still stay under my MAF HR. 🙂

    • Andrew:

      Sorry about that—I must have missed your comment somehow. That’s correct: your heart rate essentially marks how hard your metabolism is working. So, even though in the pool, your heart is working harder, your body as a whole isn’t.

  • David Burns says:

    I did my first MAF test 50 year old male. Mile 1 11:08 HR 127 Mile 2 11:35 HR 127 Mile 3 11:46 HR 126. Is this a good start it seemed slow.

  • Susan says:

    I had been given information on a friend on this method of training and am going to start today. Recently my runs have been a lot of speed sessions where my heart rate is around 90% of max and at one point last week hit a peak of 202bpm when racing a 5k. I am not seeing much improvement in my running and do tend to burn out rather easy.

    I plan to try the test today on a treadmill. I am 24 years old and there fore my range will be 146-156bpm. So do I walk/jog/run a mile while maintain my heart rate around 146-156bpm and record this time?

    Does anyone have any advice for starting the training?


  • Nick B says:


    I stumbled upon Maffetone method this spring looking for a new direction in my running. I’ve been following the method quite well over the last few months. I’ve been building my volume at a slow rate and have worked up to 8 or so miles per week. With my longest run being 4 miles. My personal HR calculates out to 142 and usually I stay in the 139-140 range. At the beginning the 138-139 HR was fairly easy to obtain and I would still be able to have a conversation while I run. However, now 139-140 takes quite a bit more effort to hold. My mile times have come down close to 60 to 90 seconds. Should I keep bumping my HR up to to the 142 limit? Or should I run based more on feel where the running is easy which would be closer to 128-130 HR? I’m planning on another month or two of base building and getting to 12-15 miles before I start with any running speed work.

  • Kedar Pitreks says:

    I have started using the Maffetone method. My max HR is 128 and after my 3rd run I managed to keep the pace so as to keep the HR below 128. The pace I run is around 8:30 – 9:00 min/km. I am facing 2 problems. One is that my cadence has to be very slow to control HR and because of this my soles of the feet have begun to hurt after a long run of 10mile and above.
    Second is that up till 10 km The HR is in the range of 124-5, but after that it jumps to 130-132 even though I slow my pace down. Is a variation of 3- 4 bpm acceptable in this method? On gradient I am virtually walking slowly!
    I stay in India and am 52yrs old. I took this up for my Half marathon timing is not going below 2hrs and invariable I run out of energy after 12-13 km and have to slow down. Pl advice

    • Kedar:

      Thanks for commenting.

      The reason you run out of energy after 12-13 Km is because your body is primarily burning sugar, instead of fats. The problem with this is that the human body has much fewer sugar stores than fat stores, so you inevitably run out of energy.

      Because the body favors your sugar-burning engine, it’s fat-burning engine is relatively weak, which means that your speed at a low-intensity, fat-burning heart rate is relatively low. The best way to fix your problem of running out of energy is then to run at a low-intensity heart rate to make sure that the sugar-burning system isn’t activated so that you can train the fat-burning system appropriately. The MAF HR is exactly this heart rate.

  • Sarah Firth says:

    My son has been diagnosed with over training syndrome Dec 14 and is under a sports physician here in the UK he’s now 19 and a sprint swimmer, he burnt himself out in 2014 as competitions coincided with exams etc. Looking at this website i would say he’s had stage 3. (We’ve addressed his diet and supplements and he continues with this). He’s hit a downturn again after doing really well for around 2 months he was energised, few troubling symptoms and his training had increased to 160 HR on the static bike 15 warm up and 15 cool down, 160 therefore for 30mins and daily walks, he also got back in the pool once/ week and was swimming 1k with short rests after every 50m, he felt great. Then the symptoms started returning, nausea, headache, poor concentration and fatigue. He’s now rested with just short walks for the last 3 weeks waiting to feel better.
    My question is should his HR not go above 150, using your formula and i think he shouldn’t increase for around 6 months to get a good aerobic base?
    I would appreciate comments please……………………

  • Karen says:

    Can this been done using intervals like Jeff Galloway.

  • kevin says:

    Hopefully I can get some advices here 🙂
    Here is my basic statistics:
    Body Fat:13%
    Vital Capacity:5500-6000(Not much changes since 18)
    HR:normally 80-85/min
    Exercise history:
    No severe injury;
    Physical Trainings:
    Weight lifting (Squat, bench press, pull-up, etc.,) for one and a half year and gained around 10 pounds of weight;
    Basketball and Swimming
    My performances in sports normally are OK. But my aerobic performance sometimes might be inferior to some guys who did no physical exercises at all and to some girls, which is kind of frustrating.
    I began MAF this year and tried around 15 times of 5km MAF run.
    My HR is around 155/min and I need around 40-41 minutes to finish 5KM. Although I might not be very tired, my shirt is all wet due to continuous sweating during the run. I wonder maybe my “Talent” in aerobic exercise might be below average. Now the question is that should I continue my weight lifting workout (Just upper part of the body) around once or twice a week while I do my MAF run twice or three times a week? Or any suggestions on improving aerobic ability? Thanks a lot!

  • Karl B says:

    Hi there,

    I wondered if this is norm as I am a reasonably speedy veteran. I am 53 years old, I can run a 5K in 19:59 and a 10K in 42 minutes and a marathon in 3:45. So I have speed and endurance.

    Based on 180-53+5=132 HR. For me, this currently equates to 10 minute miles for me. That seems remarkably slow compared to what I normally wrong. Is that normal?

    Thank you for your time.


  • NRC says:

    Hi all.

    I’m new to Maffetone-style training and have a few questions. I tried to search through many of the previous questions/answers but didn’t find anything quite on point. Anyway, here goes.

    I conducted my first MAF test on my usual 3 mile run on May 31st. I expected that I’d need to run very slowly and maybe even walk portions to stay at or under my MAF HR of 139, but yowzers, I needed to walk quite a bit more than I expected. Even when I’d suddenly stop running when I hit 139 and transition to a walk, my HR would continue to climb well above 139 and it took some time for my old ticker to ease back down to below 139. Given this, my average HR over the course of the entire run was 141, a few clicks above my 139 target. My question is, did I botch the test? In other words, should I do it again, perhaps setting my HR sensor at 135 to build in a “cushion” so that I do not go and stay above 139 so easily?

    My second questions is whether I’ve started my MAF base building too late to properly prepare for a marathon (my first) in November using this method? During my 3 mile MAF test, my average mile run was 14:38. Is it possible to get relatively quick improvements so that I’m at least consistently slowly jogging at or just below my MAF HR so that I can increase mileage in preparation for the marathon?

    Any feedback is appreciated.

    Thank you.

  • Hello. I am new to the MAF method and the diet Dr. Maffetone recommends. I do understand the basic principle and believe in its benefits. However, I am finding it difficult to translate to my situation. I’m 48 and have run 10 marathons since 2007; best 3:26 in 2011 (BQ try); 3:42 most recently in May (with no particular time goal). 10k of 44:20 in 2014; 5k 20:40 in 2012. I typically train min 40 miles per week (6 days); increasing to 60 before a race.

    I have been running MAF consistently for three weeks. My current MAF pace is around 10:40- on a good day. It has been 12:30 on the recent warm, humid days we’ve had in NJ. My HR also spikes quickly during a run which causes me to walk to get back to MAF. I can’t seem to get my head around the fact that this “slow” pace at 137 bpm will somehow come down to into the 8:00 range by using only MAF runs. My goal is to BQ at 3:25 (within the next 10 months; hopefully sooner).

    Given this info, is it simply a matter of sticking to MAF and following the diet or would you think there are other issues with me given how far apart my MAF is from the 8:30 pace of my recent marathon (which was mostly run at a very comfortable level)? If so, i hear MAF is a high volume approach. What is the recommended time/miles per week to be most effective? Am I completely broken? Help!

    Thanks for any thoughts.

    • Henry:

      The best recommendation I can give you is to keep to a training volume that is similar to what you have already done. Then ramp it up slowly, without overly stressing your body.

      MAF doesn’t have to be a high-volume approach as long as it’s done right: making sure that you give the body a training volume that it can easily tolerate, and allowing it to grow instead of pushing it towards better performance. (That better performance will come as a function of its growth, and it will correspond to a greater tolerance of training volume).

      • Henry says:

        Thank you for the response Ian! Much appreciated. I can report that my HR is much more stable now and I feel my MAF pace is improving. I’ve been running 40 miles per week or so; i feel my form is getting more efficient as well as I’m able to focus on it at the slower pace.

  • John H says:

    My MAF range is 120 to 130. Does that same range apply in cool weather (say 45 degrees F) as in hot weather (say 80 degrees F and sunny)? Or with dew point of 75 versus 55? Or does one add on some beats for heat?

    Also, the warm-up. I noticed in a previous reply that you have a warm-up 1.5 miles when you do a 10 miler. How does that work? Do you run at even a lower HR? I assume that the warm-up can be anything that gets your HR up.

    Thank you!

    • John H:

      You don’t add any beats for heat. This is because the body’s thermoregulatory response (which includes sweating) uses up a lot of energy (the skin is the largest organ in the body). Now consider that the MAF HR corresponds to the intensity at which you’re burning the most fats. If you start sweating your body will need more energy. If it is not able to get that from fats, it’ll get that from sugars.

      Here’s a second piece of the puzzle: the hormone responsible for activating the systems that increase the availability of sugar is cortisol, which is the primary stress hormone. This means that as soon as the demand for fuel exceeds the supply of fats, the stress on your body will increase by virtue of the increase in the availability of sugar. And because a certain amount of sugar is necessary to keep burning fats, as the thermoregulatory system uses up sugar, cortisol will have to increase yet again, in order to expand the availability of sugar in the face of a dwindling supply.

      (And I’ve mentioned nothing of the autonomic fatigue (of the nervous system) due to a higher heart rate, which only compounds the stresses I described above).

      This means that increasing your target heart rate commensurate to increases in ambient temperature will very quickly turn a theoretically aerobic workout into an extremely stressful endeavor. Because the aerobic system—not to mention the body’s ability to recover and grow—depends on a lack of stress, there’s very little chance that the aerobic system can grow from such a workout.

      (The thermoregulatory response may develop in spades, but part of the problem is believing that we’re developing one system while actually developing another).

      We suggest that people warm up for a minimum of 12 minutes (I do 15).

      Warming up is not specifically about getting the heart rate up there, although it is a part of it. When the body is at rest, the majority of the blood is moving around in the internal organs, and relatively little of it is moving around in the muscles. The function of the warm-up is to slowly increase activity levels so that the blood has a while to leave the organs and head over to the muscles. (A slow increase in heart rate helps drive this process). But if activity has a very quick onset, the body is going to get the message that the leg muscles need blood immediately. This means that the muscles in the core are going to contract, the heart rate is going to skyrocket, and the valves within the blood vessels are going to open and close such that blood is shunted to the legs.

      The combination of the stress (which is what allows these changes to happen quickly) and the rush of blood exiting the organs can cause the organs to go into shock. (Shock is defined as “the abrupt and undue interruption of a process”). Even if the organs don’t go into shock, the more abrupt the changes, the more they wear down. In other words, the reasons you want to warm up the body are the same ones why you want to warm up a 1980s-model vehicle.

      The cool-down is as equally important, but for other reasons. When you don’t cool down, and your heart rate immediately drops, the blood currently within the muscles doesn’t get a chance to be drained out of them. Consequently, blood pools within the muscles. This is “dirty” blood, containing relatively large quantities of CO2, acidic hydrogen ions, and other by-products of exercise. The longer it stays within the muscles, the more of a chance it gets to damage them. And because the muscles are still being damaged, they are not going to start recovering in earnest until that blood has had a chance to leave.

      So, the warm-up allows exercise to be a less stressful endeavor for the body. Cool-down allows recovery to happen effectively and in a timely fashion.

      • John H says:

        Thanks for the detailed answer. I ran 50 minutes in 90 F heat and 75 F dew point and sun yesterday, and stuck with the MAF HR. It went well. And anecdotally, I would have to say that it felt less stressful. In the past, I would run 3 or 4 miles max in that kind of heat and feel spent, but after yesterday, I think at MAF HR I’d feel comfortable going much longer.

        Many things about MAF training on the surface seem counter-intuitive (at least to me), and it’s very interesting reading the science behind it. I’m 2 weeks into MAF, and it’s been a mental struggle. I end up running about 3 minutes a mile slower than I was pre-MAF, and it’s taken a while for me to get comfortable with that kind of pace, especially since I like to attack hills and run negative splits.

        I will definitely up my warm-up and cool-down game. In a busy world, it’s easy for me to skip both of those. But you’ve given me a different perspective on why I should be doing them.

        I’m at the beginning of a training plan for an October marathon (my 16th). I like my training plan, and it’s worked very well for me, so it’s going to be hard for me to stick with MAF. Initially, I’ve been converting the miles to the number of minutes that it would have normally taken me. And then I’ve been running those number of minutes at MAF HR. Of course, this means I’m running less mileage than I normally would. Should I keep up with that conversion? Or should I go back to miles? Or should I do minutes during the week, and miles for the Sunday long run?

        • John:

          Minutes during the week and miles for the sunday long run sounds like a good idea. But what I would do if I were you is try out all versions of this and see what works best for you! Typically, if you’re running some faster miles, you want a lower mileage altogether.

  • Stephen Lewthwaite says:

    Help. I’ve just done the MAF test. I am no runner but would like to start again I mainly cycle 14 hrs/wk but wanted to do the MAF test on both. So I did 1 HR bike at 142bpm held stable wattage and good speed very happy. Note I did 180 – ( 43 + 5 ) = 142. Note a good bike workout.
    However the run, it felt fast I warmed up etc…it was fast for me 4.46km per minute. Years ago I used to do ironman but I’ve not done any running for 2 years and I would never run or train at that pace. Everyone says that MAF is too slow when they start running I felt the opposite, my quads a little rusty are saying it was a bit fast.
    Do I slow down in training or toughen up and keep going for the month and see how the next test comes out? Note also a bit overweight for me at the moment 75Kg height 172cm. In the past 65 to 67Kg. Did the whole high carb thing fruit veg lifestyle for 2 years. Now first week of Ketogenic / low carb. I will lose weight hence expect to move Faster not sure the leg muscles will like it. Run test 15 mins and I was happy to walk afterwards.
    What approach should I take with my run training given the bike is fine, the run feels fast?

    • Stephen:

      It’s not a problem. MAF tests can feel fast for people that are good athletes. It just means that you have a well-developed aerobic system. If it feels too fast, and you still think that the 180-Formula isn’t working for you, your best bet is to go get your aerobic threshold (fat max) tested in a laboratory.

  • Donna says:

    I have been using the MAF method for 5 months. I am 55, HR 125. Before MAF I have run 25 to 50 miles per week depending on training. My easy pace used to be 11:30, 5K pace 8:40, 1/2 marathon pace 9:30, Marathon pace 10:00. I finished my first marathon in Nov. 2014. Training felt great but I ended up with a stress fracture in my right femur. After recovery under a “running doctor” who brought me slowly back, walking then running, I discovered, then started the MAF in January 2016. My diet is very good: no refined carbs; whole foods; lots of veggies and protein.

    So, I am just not sure I am seeing any improvement. My MAF test pace is around 16 to 17 min miles. Goes up and down each test but still in the same overall range. I can actually walk faster than run, but then I can’t keep my HR high enough. The one improvement I think I see is that my HR is very consistent now, I can easily keep it at 125 where at the beginning it jumped up higher a lot. My form feels so awkward at this pace, I feel stress in my SI joint at this slow pace. A week ago I set aside MAF to run a 5k . I ran it at a 10:12 pace (much slower then before MAF) and my HR was 180 at this pace. I was very discouraged that my HR got this high at this slow pace. I had my yearly physical recently and am very healthy, all bloodwork great, I used to be vitamin D deficient but now it is really good. Right now it is very humid outside, maybe this is part of it. I have starting pool jogging to supplement training, some bike riding, trying to find other ways to get my HR at 125 without the stress of this awkward jog. I believe in the method when I read of other’s experiences, but waiting for the magic to happen to me. Any suggestions??

    • Donna:

      The shift that you talk about—from having your heart rate all over the place, to it becoming more consistent—is known as “coupling.” It means that internally, the different parts of your body are learning to work together at similar rates. We don’t talk about coupling (and its inverse, “decoupling”) because it’s a complex topic, but essentially, a certain degree of coupling is a necessary precondition for the body as a whole to begin developing aerobically.

      So, while your speed hasn’t improved, your body as a whole certainly has.

      Another very important consideration to make is the interplay between stress and fat-burning that occurs within the body: fats can only be burned at a lower level of stress as indicated by a lower (MAF) heart rate, and above that, you start increasingly burning sugar. The key point here is that “stress” is a measure of how well the organism can deal with environmental demands (such as running). If one femur is weaker because it never regained its old strength, there is one part of the body that can deal with far less stress than another. In other words, your femur may be your weak link.

      What does this mean? It means that it doesn’t really matter how strong the strongest link in the chain is: the chain snaps at the weakest link. So, in terms of stress tolerance, your body as a whole may not be able to rise to a certain speed because, say, the stress of running at a 13 minute mile is easy for your body, but maximal for your femur. And because of that, your body as a whole (a.k.a. the chain as a whole) reacts to that 13 minute mile as if it was a maximal or near-maximal exertion.

      So I’m not trying to say that it necessarily is the femur that’s holding you back (it might be completely healed AND perfectly strong), but I wouldn’t be surprised if it was a contributing condition.

      2 recommendations: walk quickly instead of running (even if it puts you 10-15 BPM below your MAF HR) and take up jumping rope. Jumping rope will also help your joint mobility in a generalized sense and prepare you better to run. This doesn’t mean that you should necessarily stop running altogether, but it’s another way to shake up your routine.

  • Hannes says:

    Hi there,

    did my first MAF run yesterday. It took me about 20% longer to complete my usual course compared to what I used to consider an easy pace, but I felt very refreshed afterwards, a nice sensation. My main question at the moment is, is it really necesary to do a MAF test every month? Shouldn’t I be able to track my progress by the time it takes me to do my usual distance? What is the advantage of comparing 1st, 2nd, 3rd mile in the MAF test as it is described above?

    thank you

    • Hannes:

      Doing a MAF test every month lets you track whether your aerobic system is improving on a regular basis. Testing daily (by using a GPS watch every run and tracking your mile splits) is useful, but doesn’t tell you that much about your aerobic development on a day-to day. While your body’s performance readiness fluctuates several times a day, the aerobic system improves on the scale of weeks and months.

      For example, if you had a more stressful commute home, your daily MAF pace might slow down. If you had a bit more greens than usual (helping along your digestion), your daily MAF pace might speed up. But this doesn’t mean that you got significantly fitter from one day to the next. It means that on the day you ate greens, your body was better positioned to make use of the aerobic machinery it already possessed.

      And if you don’t do a MAF test every month, you might not realize until 3 or 4 months down the line that the training volume you’ve been doing has been too light (which is one of several reasons MAF speed doesn’t improve), or too heavy (in which case, your MAF speed will have either not improved or dropped). Testing your aerobic system on the timescale on which it develops (a.k.a. monthly) is the best way to know you’ve been improving.

      The advantage of comparing mile splits is that it tells you a lot about how much aerobic base you keep in reserve. The degree of slope tells you how much aerobic endurance you have. A very steep slope tells you that you have very little endurance, while a slope of 0 (or nearly 0) for 12 or 13 miles means that it’s reasonable to suspect that your aerobic system is ready to run a marathon.

      For example, someone who has been sedentary all their life may have a dramatic slope between their 1st and 2nd mile MAF Tests. This is because their aerobic systems are neither very powerful nor have a lot of endurance. For example, a D1 22 year old 5-k runner might have very fast MAF times for their initial miles, but observe somewhat of a drop-off towards later miles. Their first 8 miles might look something like this: 6.5, 6.6, 6.4, 6.5, 6.4, 6.9, 7.7, 7.8. On the other hand, a decent marathoner’s MAF tests might fluctuate between 8.3 min/mile and 8.5 min/mile for the first 16 miles, and then start dropping .3 min/mile every mile after that.

  • Hannes says:

    Thank you for your explanations, Ivan. I didn’t mean to compare MAF speeds on a daily or weekly base, rather take say the average MAF speed of the first couple of training sessions of one month compared to the average of the first sessions of the following month. Cause it seems to me that the MAF speed in a MAF test can also vary due to a number of reasons some of which you explained above, so comparing e.g. a MAF test on a cool day in April to a MAF test done on a rather warm day in May might give misleading results. But your explanation concerning mile splits definitely makes sense and I guess that the slope between miles depends much less on external factors than the MAF speed itself?

    You also mention training volume as a limiting factor in improving MAF speed. I’m 48 and I’ve been training regularly for 3 1/2 years now. Due to time constrictions I only train 2x a week, usually an 11.5k and a 15k run, adding some 34k runs off season in preparation for the first marathon. Last year I had a very consistent season with 3 marathons between 3:55h and 4:00h and 5 or 6 races between 10k and 10mi with paces between 4:50 and 4:55/km. Would this volume be sufficient for making progress training after the MAF method?

    Thank you

    • Hannes:

      Yes as for the slope, unless say you were doing a 10 mile run and it got 10-15F cooler the second half of the run.

      That might be enough volume for you. The best way to know is to check and see if your MAF speed is improving or not, on a monthly basis. When you’re doing relatively little volume, you should observe that your MAF speed progresses quite slowly, rather than remaining at a complete standstill. (This is to differentiate it from overtraining: the typical plateau that occurs in OTS before your speed starts declining is almost perfectly flat).

      But when you’re in your ideal training volume, and increasing it periodically, it’s typical to observe 10-15 second per mile gains (at the same heart rate) for 1-2 years. People often end up 2min30sec faster per mile 2 years later.

  • Joe says:

    Hi, I’m new to the MAF method and am impressed with how I feel on a ketogenic diet. I will be using this for a long time. I train for 50 and 100 mile races and typically finish in the top 10%-15%, but have been unable to get any faster. To me training at MAF seems impossibly fast compared to what I’m used to. MAF is 150 bpm = 8:15. I’m used to about 132bpm for 80% of my miles. My question is is it possible to run at MAF for over 24 hours? And should I be expecting to race at close to 150? What would you think my average HR should be for a race this long?

  • Mark J says:

    I am in the midst of training for a mid-September marathon.
    For the weekly Sunday “long” runs, is there any reason to do those faster than my MAF pace (HR=145 bpm)?

    Also, the training plan I use has 2 off days, 2 easy days, 2 hard/tempo days, and 1 long run day.
    Is having 2 hard days per week too much if I want to keep increasing my speed?

    I am debating whether or not to just run all of my scheduled daily miles at the MAF pace and see what happens and avoid doing the 2 hard days.

    Thanks in advance for any advice!

  • jason hall says:


    i am rehabilitating from some arch related injury,changing form totally aswell and came across maf training so decided to combine that in a last ditch attempt to go from 0km to a 50km ultra again in 3 months. i am 2 months into that now with 5 weeks to go until my 50km(2600m gain) trail event. my MAF is 142 and i have been increasing 10% per week mileage and am back to 44km this week for eg(48next week and so on until race day).

    in your opinion would you keep on that stategy of 100% MAF increasing distance 10% all the way ? for the last month i am going to increase my longer runs up 10% aswell.

    should i do anything over MAF like one 10k run at 155 or something and what would you recommend i race at ,to be honest MAF pace is very hard on my knees(6min30 per km,177-185 cadence,midfoot,0.84mtr stride length) compared to a heart rate of 150-155 where i can get moving and push bit more in a forward direction and not so up and down so i would love to race above MAF on the flats just to protect the knees over 50km distance.

    my training base is far from ideal currently to run 50km but i will do anything i can to ensure i can get to, and run that event injury free and any suggestions you provide are appreciated:)

    • Jason:

      Yes, that sounds like the best option.

      However, you shouldn’t have to run faster than MAF to protect your knees. Shorten your stride and quicken it. Practice that, and you’ll start getting much faster much more quickly at MAF.

      Essentially, lengthening your stride is an easy way to get faster. However, it’s also the wrong way. Think of your hip extension as your “gas pedal.” Once you max out on your hip extension at a particular stride rate, you’ve maxed out on your speed. The thing is that the reason you chose to lengthen your stride instead of quickening it (and keeping it short) in the first place is because quickening your stride means much more muscle development in the immediate term than developing it (which means that it’s costly and the body doesn’t want to do it).

      So, by quickening your stride first, not only do you protect your knees but you also open up room for growing in maximum speed.

  • […] trying to stay within my aerobic heart-rate threshold. If you haven’t heard about this MAF training by Dr. Phil Maffetone I recommend checking it out, it’s fascinating stuff.  The short of […]

  • AJ says:

    I’ve been doing MAF training now for 4 weeks after a year of knee and back injuries and I’m really struggling to keep any kind of consistency or stability with my heart rate while training on my treadmill. I do appreciate that I do not have great fitness at the moment and I am probably still 14lbs over weight. At 37 my MAF score is 143. If I walk fast on the flat I can’t seem to hit 143 and when I increase the incline I can’t stop my HR from going past 143. I can’t seem to find that sweet spot where my HR has any stability. Is it better to be just under your MAF score when training or just above? or does it not matter as long as it stays within a certain tolerance, say 5% + or – ?

    I also find that outside factors change my HR by quite a bit while training, for example if I’m training and my kids walk in from school my HR goes up a little, my wife comes home from work it goes up by a lot. If my Mother in law walks in my heart rate can go above 143 just sitting down. Should these outside stress factors be accounted for when training to a MAF score, such as… 180 – age -5 for previous injury +5 for kids at home ?



    • AJ:

      Thanks. No, in fact, it is precisely because stressors can and do alter our physiological state that it is best to go by heart rate (which is the simplest indicator of our overall physiological state). Think about a gazelle that is frightened that a lion is nearby. The systems that help them escape from the lion (a.k.a. the anaerobic system) are revved up and ready to go. That’s the point of stress. So, any increase in heart rate essentially means that those systems are getting revved up by a threat (a.k.a. your mother in law), and that’s what the body is primarily using.

  • Eric Houser says:

    I have a question in which appears to have been asked before, but without a clear answer. As a previous poster has asked, and my situation is very similar, almost to a T, if the MAF method is geared to be more individualized (since it was stated there are no cookie cuter approaches since everyone is different and unique) why is the standard formula of 180 used, give or take a few based on some common factors? My history is also similar as above. I have been been running for 25 years, 16 ultra-marathons, a couple multi-days, a 24 hour and many adventure races as well as prior military infantry. I have had my heart rate tested for “heart rate at threshold” and it’s 177 and I can also get my heart rate to 205-208 during an ll out effort during short duration race such as a 5k. I understand the premise behind the MAF method, but cannot grasp the idea of not having a more individualized test or method for those of us who fall outside the norm. I have questioned the HR situation before, and the typical responses are, “your HR strap is defective”, well, no since I have had no less than 5 of them and they’re all the same and I have heard, “you must be out of shape”, again no, at least in my opinion. I have heard however this is common among people who have a smaller sized heart?? This causing the heart to have to pump more than a normal sized one. All this aside, I still question if there is no other factor for those who have a typical higher heart rate. My resting heart rate is in the mid 40s as well.

    • Eric:

      The threshold you have been tested for (177) is most likely the anaerobic threshold (also referred to as “lactate threshold,” “2nd lactate threshold” or “LT2.”) The aerobic threshold (also referred to as the “1st lactate threshold” or “LT1”) typically occurs at a much lower heart rate—that’s the one the 180-Formula attempts to measure. I can count on 1 hand the number of 30yr old elite endurance athletes whose LT1 might occur (on their best day of their career, towards the end of their best-ever base-building period) in the neighborhood of 165 BPM. I don’t know of anyone whose LT1 would (say, could) occur above 170. Perhaps Kilian Jornet or another one of those 1-in-a-billion 90L Vo2 Max guys, and then again, only before their first race of the season, at the very peak of their careers, and with a really generous lab technician.

      The formula is just a formula; meaning that it’s the best quick-and-easy way to reasonably ballpark LT1 without any equipment. It works for a majority of the population, but not for everyone. If you want to find your MAF HR as indicated by a laboratory, go find your VT1 (first ventilatory threshold) and your LT1 (sometimes also known as Fat Max). Your LT1/Fat Max (which is also your MAF HR) should occur a few BPM below your VT1. I suspect that your LT1 will occur in the ballpark of 155 BPM, supposing that 177 is your LT2.

      The MAF HR (and the LT1) isn’t a measure of cardiovascular potency, but rather a measure of metabolic potency. Specifically, it is a measure of the rate of fat-breakdown (lipolysis) which needs a certain combination of hormones to occur. In other words, LT1 is a measure of the efficiency of the fat metabolism, which isn’t really related to the power of the heart.

      If the energy demands of the body exceed the rate of fat-breakdown, the heart rate will increase. But this increase is almost always NOT because the demands on the heart are significantly greater, but rather because the stress hormones needed to increase the availability of fuel (sugar) independently increase the heart rate. So, the heart rate’s initial rise above the MAF HR is a consequence of needing more fuel of a different kind, rather than a consequence of needing more blood to pump more quickly around the body. After a certain point the heart rate’s rise due to fuel-related hormone changes isn’t enough to get fuel and oxygen to the muscles, and heart rate has to rise independently of those fuel-related hormonal changes. That’s the point where the body’s cardiovascular power really begins to matter. It typically occurs close to (if not at) LT2 and VT2.

  • George says:


    I have a question. I have been training using MAF method for 1-2 years now. I have clear progress. I am 24 so I run my MAF HR is around 155-158 (I train quite a bit, 6-7 days a week for the past 3+ years).

    The progress is quite good, I used to run around 8:20 MAF pace when started and now run 6:55 mile pace at my MAF effort on the track.

    I have a few points/questions, on which I would appreciate your comment from your experience:

    Question 1: when I do my MAF testing, I run around 15 min to the track, building up my HR to around 152-155. Then I enter the track, take 1-2 min to prepare for the test and run 3/4 of the lap to build my HR to the my MAF HR of around 155 and when I hit the start line on the track I start timing the miles every 4 laps.

    Is that the right approach? I have read the big yellow book and though Phil is quite descriptive about the test and warm up it does not quite answer a few important questions. Do build up to your MAF HR and start timing the miles when HR is already at your MAF max HR or you start from rest?

    I find that this would affect the test a lot as I can run much faster to build up my HR to the necessary level.

    I would appreciate if you could comment whether my TEST protocol is correct to get the right results…

    Question 2: The other thing is, sometimes I find it hard to make MAF tests in exactly the same conditions i.e. amount of rest and how fresh the legs are. For example, around 2 month ago I did a MAF test when I was quite well rested and scored first mile at 6:55. That was my first run of the day and I was quite fresh. I did another test yesterday, which was in the evening after work and with a 5k run in the morning prior to that (not so fresh), also my legs were still tired (quads hurting a bit, no pop in the legs) after a hard long mountain run I did a week before. Still, I ran 6:57 which I see as a progress because basically fresh me two month ago is the same as tired me two month later.

    Is that a correct view?

    Question 3: As I described in Q2, what I also did is I started doing weekly track sessions of Vo2max speedwork (approx 25min of pure effort). I have noticed that my high end speed increased greatly over the past few weeks. In addition to that, on some runs the next two days after speedwork I feel as if my MAF pace gets some real boost, I would just run faster than usual by around 15 secs per mile and my HR would still be in MAF zone.

    What does that mean?


    • George:

      1) You start the MAF test once you have completed your warm-up. In other words, you only test miles done at the MAF HR.

      2) Yes, absolutely.

      3) When training anaerobically, your entire system gets a boost, in order to repair damaged muscle and fuel those anaerobic muscle fibers. So your metabolism is driving harder than it usually does. While it is OK to train aerobically in a circumstance such as this, it is very easy to transition into overreaching when you mistake this for an increase in “fitness.” It is not. It’s because the metabolism as whole is working harder, but it does not indicate further development of the aerobic system. In other words, it represents an inflated function of the aerobic system. Elite athletes time their training so that they achieve this boost at or just before a race—a practice known as “peaking.”

  • Juan says:

    Hi Ivan, I have 2 questions.

    1) Is there any need to do an MAF test if one is aerobic base building with the same routine every workout? Eg if I’m aerobic base building with a stationary bike (assume the same bike at the same gym), every workout is a mini MAF test. So if every week I can do more RPMs at the same resistance, that shows improvement and obviates the need for an ‘official’ MAF test. In other words, is there anything special about the 30 minutes biking or three miles running used as examples in this article?

    2) In the situation of question 3 posed by George above, is one still aerobic at the MAF heart rate? No adjustment should be made?

    Thank you.

    • Juan:

      Great question!

      1) Yes and no. Tracking your heart rate every day is useful, but a lot of the variability between one day and the next doesn’t really have to do with measurable increases in your aerobic development. We like to say here at MAF that the aerobic system develops in the course of months, not days. So, what you’re really seeing on the day-to-day is your daily stresses, daily hormonal fluctuations, daily impacts of weather, daily differences in fuel storage. The “real” picture of what’s happening will come together when you look at 3 or 4 different tests (or 3 or 4 months’ worth of daily “MAF Tests”). So if you’re doing the daily HR tracking, you don’t absolutely need to set aside time to do a formal MAF test. If you take, say, your 60-odd workouts over the course of 3 months—or even 1 month—and zoom out and look at the major trends), you’re getting a substantively real picture of your aerobic development).

      However, what I do recommend is that if you can additionally do monthly MAF tests in the exact same environment (same dinner, same breakfast) and on a treadmill in the same temperature, you’ll get an even better picture of your aerobic development, particularly when you contrast those MAF tests with the rest of your exercise.

      2) Yes, you are. The body just has the aerobic system revved up a little too much, but that’ll wane. But it’s still aerobic.

  • Henry Mroczko says:

    Hello. I posted back in June when I was starting my MAF journey. I haven’t run above MAF since June 1; running about 7-8 hours per week at MAF (137). I’ve also stuck with the diet suggestions.

    My MAF pace has come down from 11:24 to 10:28 in my fourth test (Saturday). However, my first/second mile pace on my normal runs (after warm up) has been in the 9:30-9:50 (best has been 9:29) range on many days. Can I look at this range as my true MAF pace even if the test didn’t confirm/match? Weather conditions on Saturday were near ideal so that wasn’t a factor.

    I’m also curious when I can add some work above MAF into the program? 9:30 MAF matches my current reasonable 5k time.

    Thanks again for the great site and advice!

    • Henry:

      Yes—whatever pace occurs most habitually for the first miles is the one you can think of as your “true” MAF pace.

      Usually, the best time to add work above the MAF HR is when you’ve trained about 3 months at only MAF. So it seems like it would be pretty prudent to add some speedwork in, particularly given your improvements. I wouldn’t do more than 10-20% speedwork (above MAF). At this point, use your first mile MAF time as a go/no go test for adding speedwork in: if you see your MAF speed plateau for more than 3 months or dip slightly, take out the speedwork for 2-4 weeks. If your MAF speed is rising (even if slowly), the training load is working for you.

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