The MAF-GPS Test


By comparing heart rate, speed, time and distance during workouts, the MAF-GPS Test, a sub-maximal evaluation, can help measure fitness progress and health status, and even raise a red flag for problems.

Maximum aerobic function reflects various physical and metabolic features important for participants in all sports. All athletes benefit from improved aerobic muscle fiber activity to support anaerobic muscles for optimal power, strength and recovery. Endurance athletes in particular rely on the aerobic system for increased fat-burning to provide long-term energy and conservation of glycogen.

Maximum aerobic function, or MAF, should be objectively evaluated year-round to avoid loss of training progress, and also to give clues about various wellness factors that reflect both fitness and health.

Years ago, I developed the MAF Test to help individuals monitor the progress of their aerobic training programs. Whether you are an elite triathlete, mid-pack marathoner, someone seeking to lose body fat or weight, or you’ve just made the commitment to get back into shape, this simple test can help measure aerobic progress, and warn of a training plateau or regression.

For years the traditional test relied on pre-measured routes, such as a track, to evaluate MAF. However, ready availability of global positioning system (GPS) devices has provided another simple method to test for MAF. With GPS, one need not rely on a local running track, but the test can be done various ways as discussed below, and anywhere void of steep hills (which make it more difficult to maintain the appropriate heart rate).

Our new MAF iPhone App has a MAF Test function that you can use to take your MAF tests systematically and observe the development of your aerobic system across time. At the bottom of the article we provide a link that takes you directly to the MAF App in the app store.

Monitoring Fitness

The body’s aerobic system is based in fatigue-resistant muscle fibers fueled by fat. It has long been recognized that the vast majority of endurance-based sports, such as running, cycling, triathlon and cross-country skiing, require most energies be derived from aerobic metabolism. For example, 99 percent of the energy needs for a world-record marathon comes from the aerobic system. For an Ironman triathlon it’s more than that, and in relatively shorter races such as a 10k run, it’s still 95 percent. Even during a one-mile event, 65 percent of energy needs are aerobic-dependent.

Athletes who run track and field, or who play soccer, basketball and other team sports, and even those performing high-level power events such as weight-lifting and wrestling, can benefit from improved aerobic function. Well developed aerobic fibers can help neighboring anaerobic fibers function better and recover faster by improving circulation of oxygen and other nutrients while disposing of unwanted byproducts within the power muscles.

Monitoring Health

The MAF-GPS Test can also help monitor health, especially in avoiding overtraining. For example, as one can run faster at the same heart rate, burning more body fat for energy follows, which leads to many health benefits and fat loss. Both versions of the test reflect efficacy of physical movement. Better running economy, for example, is associated with faster paces at the same heart rate. This is most likely associated with the body’s ability to self-correct muscle imbalance more quickly, in addition to having more energy from fat. As such, aerobic progress is usually accompanied by reduced rates of injury, and a lower risk of overtraining.

The traditional MAF Test measures two workout elements — such as time and distance — while maintaining a constant sub-max heart rate. A review of the original test can help better understand the GPS version.

The Traditional MAF Test

I developed the original MAF Test around 1980. In common use today, it consists of measuring an athlete’s workout while maintaining a sub-max heart rate. (The sub-max heart rate corresponds with low- to moderate-intensity training. See the 180-Formula on how one can determine maximum aerobic heart rate for training and testing.)

An example of a runner performing the test follows:

  • An easy 12- to 15-minute walking or jogging warm-up.
  • A run consisting of a predetermined distance, such as three, four or five miles, at sub-max HR, with each single mile time recorded. Beginners or walkers can use a one-mile (1.6 km) test.
  • A 12- to 15-minute easy active cool down (if this is the end of the workout).

It’s best to perform each test on the same track, time of day, and wearing the same shoes. The test should not be performed during inclement weather (including unusually high or low temperatures, rain, snow, or excess wind), or during illness.

Below are the results of a runner’s four monthly outdoor track MAF Tests consisting of three miles each.

Test 1

Mile 1 8:44

Mins/mileMile 1: 8:44
Mile 2: 8:52
Mile 3: 9:10

Test 2

Mile 1 8:36

Mins/mileMile 1: 8:36
Mile 2:
Mile 3: 8:57

Test 3

Mile 1 7:58

Mins/mileMile 1: 7:58
Mile 2:
Mile 3: 8:10

These results are the expected norm in a healthy athlete. Some individuals progress at slower rates, while others faster. Within a single test, progressive mile times are usually slower, due to mild fatigue. With aerobic progress, three results should become evident:

  • A faster pace of test miles each month.
  • The gap between the first and last mile becoming more narrow reflecting reduced fatigue, increased fat-burning, better economy or other factors.
  • For competitors, there is a direct relationship between aerobic progress and anaerobic performance. Improved MAF Tests lead to quicker race times. Using resulted determined from traditional MAF Tests on a track, for example, if a runner’s first mile MAF Test is 8 minutes the expected per-mile pace for a flat 10k is around a 6:30. In a marathon, the expected race pace on a typical course would be about 7:45. (Other sports have not been measured with this level of precision.)
The most common question about the MAF Test is, “What happens if I don’t improve?”

Red Flag: Caution!

If the above results are not forthcoming, it should be a red flag. The most common reason for this is a lack of aerobic improvement with potentially, any number of problems being the cause. Likewise, a test with worsening results, such as slower times, may be a more serious problem as training is regressing.

The reasons for the lack of progress could be many, but a common cause is too much high-intensity training as described in a case history below.

The chart below reflects MAF Test results of a runner during a 19-month training period using the same relatively flat 5k course. Training during month one through 12 was exclusively at the sub-max MAF heart rate, followed by a period of seven months that included substantial anaerobic intervals and weight-lifting. The runner’s progress plateaued quickly at the onset of anaerobic training, and began deteriorating after three consecutive months of high-intensity training. In this particular athlete, this regression reflected the earliest stages of an overtraining syndrome. (By returning to aerobic-only training, not shown on the chart, this runner was able to ultimately improve MAF Test times again.)



MAF Test Chart

Various versions of the MAF Test are used for other sports such as cycling, rowing, walking, cross-country skiing, motor sports and canoeing, with athletes in basketball, soccer, football and other team sports performing the test while running or on a stationary bike. Different performance measures are often employed that include the relationship between sub-max heart rate and two other factors of time, distance, pace/speed or power (watts). The use of GPS has made the MAF Test much easier.


The implementation of the MAF-GPS Test is similar to the traditional test, follows the same logic but can be performed almost anywhere. One can employ it during regular training runs, rides, hikes and other workouts, even rowing or paddling on a waterway. The GPS will provide information about distance and time. But it’s important to use the same course each time so an objective comparison can be made. Activities should also be evaluated for at least 15 to 30 minutes.

Here’s an example of a cyclist riding three loops of a road course. The first loop took 28 minutes, the second 32 and a third 37 minutes. A month later, loop times are 26, 29 and 33 minutes. You should now be able to apply this same concept to your particular workout and sport.

Another GPS measure to consider is distance covered over the same time frame. If you normally work out for an hour, for example, building the aerobic system should result in a faster pace leading one to run, ride or otherwise cover more distance during that one-hour period.

Whatever method of measurement used for your MAF-GPS Test, stick with it so you compare the same test format.

5 Ways to Test

Below are five specific ways to test aerobic development using GPS. (Except for No. 3, all can also be performed with just a heart-rate monitor and watch.)

  1. Minutes per mile or kilometer. Following the traditional MAF Test format, one measures minutes per mile or kilometer. One should become faster per mile or km.
  2. Course time. Measure total time of your test course, regardless of the distance (which you’ll know from GPS data). Course time should get faster.
  3. Distance per workout. Determine the distance traveled during your regular workout. A one-hour workout, for example, should have more distance covered.
  4. Power meter (watts). How much power output is measured over the test course, or during the workout period.
  5. Pool laps. The number of laps in a pool in a set time. A swimmer can perform more laps in the allotted timeframe.

For those with a long history of traditional MAF Testing, you can still use GPS on the track, especially for the ease of recording the data into your iPhone. The new MAF app enables users to do this while working out.

But one need not wait a month to monitor progress. An MAF-GPS Test can literally be performed during each workout. However, daily monitoring runs the risk of an obsession similar to stepping the scale each morning. Our normal circadian variations in human physiology may fluctuate from one day to the next and not be measurable. Sometimes, the day to day variation may even appear negative as certain days the body just does not want to go as fast. But as the weeks pass, overall changes are more consistent and easily observed.

The MAF-GPS Test, like the traditional version, can help take the guesswork out of training by objectively measuring progress, and even prevent lost training time, injury and overtraining.

GPS as Radar

For decades, athletes have checked their morning heart rates, with an elevated number being a forewarning of a problem, such as an oncoming cold or flu, or other stress, even a potential injury. More recently, we have learned that heart-rate variability can provide radar-like warning of potential overtraining or poor recovery.

Both MAF Tests work in very similar ways, but with a more fined-tuned measure and more precise numbers, especially for those who have a good track record of testing.

In addition to an early onset of overtraining, as highlighted in the example above, other factors can prevent aerobic progress. These include poor mechanical (such as an altered gait), metabolic stress (reduced fat-burning) or hormone imbalance (such as an increase in the stress hormone cortisol). The result is you run, ride, or otherwise workout slower at the same heart rate as the days and weeks pass.

Along with excess anaerobic/high-intensity training, weight-lifting, and or racing, as shown in the example above, two other common problems that could impair aerobic progress include:

  1. The intake of refined carbohydrates, which can impair fat burning and reduce the extra energy needed to go faster (especially when these foods or drink are consumed right before the Test, or workout).
  2. Inadequate recovery, typically from previous workouts or recent weeks of accumulated training and or racing, or poor sleep.

Click on the button below to get the MAF iPhone App and take your MAF tests easily and without hassle!



  • Trevor says:

    I’m now 52. I ran 5 marathons in my mid thirties. I was up to marathon distance in training about 3 years ago. I’ve been lazy for the past 3 years and gained some weight, but I have been semi-consistently going to the gym doing squats 2 – 3 times a week for the past 2 years.

    My max heart rate according to the formula should be 123 (180-52-5). I cannot run AT ALL and keep my heart rate below that level. If I break into a run (as opposed to a walk; meaning both feet are off the ground simultaneously) for even 20 strides at the slowest pace I can possibly run, my heart rate will quickly exceed 123. Even walking uphill can get my heart rate above 123.

    I’m not sure how I could possibly do a MAF test because I simply can’t run and keep my heart rate below or at 123. I can only trot a few steps, then walk, then repeat.

    I’m baffled. Am I missing something?

  • Pierre says:

    I am starting to do the MAF method from tomorrow using the app (Android). I am interested to know if I can export my session as logged in the app. I have been using the H7 for years, and it tests well with my app. However, I still want to send my training sessions to Polar Flow (and onto Strava). The problem is that the H7 does NOT connect to the app and watch AT THE SAME TIME, so there is no way to have my HR data recorded by both the app and watch.

    My answer was to keep training with my Polar and do the monthly MAF and weekly RHR tests using the APP. Where I live I don’t want to be running with my phone.


  • Fred says:

    Is it possible to see my splits in the app for my MAF test? I’m using an Android phone.

  • Han-Lin says:

    Here’s are examples of splitting rides vs having longer but fewer ones.

    Athlete 1
    M 30 min at 8:30 AM, 30 min at 5:00 PM
    T 30 min at 8:30 AM, 30 min at 5:00 PM
    W 30 min at 8:30 AM, 30 min at 5:00 PM
    T 30 min at 8:30 AM, 30 min at 5:00 PM
    F 30 min at 8:30 AM, 30 min at 5:00 PM
    Total duration: 5 hours

    Athlete 2
    M 90 min at 8:30 AM
    W 90 min at 8:30 AM
    F 120 min at 8:30 AM
    Total duration: 5 hours

    Are you saying that athlete 1 would get fitter because we assume the law of dimishing returns from the training stimulus? I look at forums and cycling articles and people still think fewer, longer rides is better. TrainerRoad thinks it’s better too when I asked them because on the second half, we exercise while fatigued. On the other hand, health experts think it’s just as good if we split them. Athlete 1 could be a commuter.

  • Han-Lin Yong says:

    What’s the science behind higher cardiac drift in less aerobically fit athletes? Is it possible that the higher threshold motor units have lower capillary densities?

    If that’s true, it seems like we should cycle with one leg at 180 minus age. For the same cardiac output, we can target more muscle fibres in the active leg. Fatigue is known to increase muscle fibre recruitment. For those short on time, they don’t have to wait until they’re partially fatigued before the higher threshold motor units are used.

    Is there a difference in adaptations when doing a long ride all in one go versus splitting it into morning and evening rides? Let’s assume that the weekly volumes are the same.

    • Han – they absolutely do; it’s been well-enough established that citing the references on this would be overkill. But there’s much more to that – the low-threshold motor units of aerobically UNfit athletes have lower capillary densities than those of the aerobically fit. And this is the case with many, many different parameters – we speculate that it is the same with say, the capillaries surrounding the alveoli, the carrying capacity of each red blood cell, the coordination of atrial and ventricular contractions of the heart. We have no data to speak of regarding this matter, but we expect that the body becomes more efficient across all (known and unknown) variables that pertain to the aerobic system and oxygen transfer and transport, rather than one or two.

      As to your second question, it’s thought that as long as the stimulus remain the same (both rides are aerobic) two rides of half the distance will have a greater effect, because it is two stimuli rather than one. What your body responds to isn’t precisely the volume or load that you subject it to, but rather the stimulation that it gets from that volume or load, and there are ways to manipulate that – this being one of the, In other words, 1+1 = 3 (or something like that).

  • Laura says:

    I’ve only been running for 6 months and worked my way up to 3 miles at an 11 minute pace. My husband saw my HR was in the 160-170 bpm range during my runs and suggested I try this HR based training method instead. I am 38 making my sub max heart rate at 142 bpm but I have a hard time staying right there. What range should I stay within? Always 142 and lower? Or should I aim for an average of 142? When I run, it shoots up to 160, then I walk and it recovers to 120. I’m having a hard time finding a consistent speed that remains at 142 bpm.

  • paul says:

    Hi Ivan, I have a couple of questions, these being,
    1. how do you calculate your race pace from your MAF results. I have just started to compete in sprint distance triathlons and duathlons and
    2. Please could you clarify if my I’m using the correct MAF heart rate. I’m 56 y o have asthma and high blood pressure, on regular medication, have trained continuously for the last 40 years and have had a broken wrist some 30 years ago. I reguarly competed up until 13 years ago, but since i stopped competing, i have continued being very active in sports. I think my MAF heart rate should be 104 – 114.
    Many thanks for your help.

  • Vlad says:

    I started training using MAF about 2 weeks ago. I’m 38, but I added 5 to my MAF HR as I’m taking some mild anti-anxiety medication and I thought that might have some effect. So I’m working with 137 as my MAF rate.

    Last night I thought I’d do a MAF test, since I had a treadmill available (thought it would be more accurate). After a warm up of about 15 minutes, I thought I had hit the “right” speed of 3.9 miles/hour where I could do a light jog and keep my HR under 137. However, after a while, it started going over 137, so I started walking at the same speed (3,9 mi/h). My HR dropped to around 125-7 and stayed there. Upon jogging again (same speed) it again jumped over 137.

    I then though I should increase the speed a bit and still stick to fast walking versus jogging, and the same thing happened (way under HR when walking, spike over 137 when jogging, while the speed did not change).

    So now, my question is, should I run the test (and my training sessions for that matter) with the fast walking (instead of jogging) if that enables me to be faster at a lower HR? And build up my aerobic base and move to jogging later, once my speed will really be fast enough that fast walking will not be an option anymore?

    I am sorry if this sounds silly, but I was prancing around for 2 weeks outside telling myself I was “running”, and it turns out my running at MAF rate is quite a bit slower than my fast walking at MAF rate. Any advice will be appreciated. Thank you.

  • Hi,

    I’ve been training using the Maf method for two weeks. I think I am starting to get the hang of it and I am more able to control my HR and slow my speed. My question concerns a couple of unusual HR jumps. On two occasions, after about 45mins and approximetly 7.5km my HR has jumped up by 30bpm for no apparent reason. I was wondering if there is any explanation for this? There was definetly no increase in intensity. I am a 44yr old male 178cm 84kg using 136bpm HR with no knowledge or history of heart problems.

  • John Garrett says:

    Didn’t see this covered but does the MAF test have rest breaks between each mile or just continuous miles?

  • TOM says:

    Hi ,
    Sorry if this has been covered above already. I’m 3 weeks into the MAF method running at 133 BPM (age42 – 5 for return from inactivity) . I done a test at the end of week 3 over 5km and my times were all around 8.30 per km, no decrease as I progressed. This was my first test. Should I be running at a higher HR ?
    Any advice is much appreciated

  • Steve Troxel says:

    I’ve been working with a friend, getting him to slow down and focus on his HR. He is 62 and has what I believe to be an extremely abnormal HR. In a 7 mile, hilly, race last weekend he ran hard and his HR was over 190 for much of the race. And, believe it or not, this is an improvement to what his HR was a year ago where he would routinely hit over 200. How is this even possible? Have you seen this before? He has become a believe in the MAF approach to training and is making good improvement but the elevated HR is just shocking. Thanks for all you do!

  • Paul de Jong says:

    Hi Ivan,

    I was reading about MAF-training on a facebookpage. I ran 2 marathons at HR of 155.
    Now I’m in training for my first ultra. I’m 54 years old, so my MAF-hr should be 126. I can add 5 because I’m in good shape and don’t have injuries for the last two years. So MAF-hr = 131.
    I also had measured my heartrate at a Sport Medical Center and there my fatbursing zone was 122-133. That’s almost the same.
    This week I started with training at MAF-hr<135.
    Today I was trying to do a MAF-test so I started my warming-up. In the beginning my hr was a little bit high gecause I was a little bit stressed by my work. After 15 min of warming-up my heartrate was stable at 134 and I started the test. Km after km I ran at MAF-hr but how longer I ran the faster I could ran at the same MAF-hr 133/134. The first km I ran in 7:01. Km11 was in 6:36. Km 12 was in 6:45 because of little climbing and the speed increased till 6:35 in km 16.
    What does this tell me? Should I ran at another hr?

    With regards,

    Paul de Jong

    • Paul:

      It most likely means that your aerobic system was suppressed at the beginning of the session, and that it regained function throughout the run. It’s also not uncommon for a reasonably fat-adapted and capable aerobic system to produce more and more power throughout a run (until fatigue sets in). Think of it as a very, very long warm-up.

      This is why, for example, MAF Test times later in the day (when the day hasn’t been stressful) may be faster than in the morning.

    • Steve Troxel says:

      This could also mean that you were not properly warmed up before starting the test. You said that your HR was at 134 at the end of 15 min – but this is your upper MAF HR. You may consider doing a longer warm up, perhaps 30 min, where you keep your HR under about 124, then enter into a test phase where you increase your pace up to your upper MAF HR of 134.

  • Ulrich Maier says:

    The problem with the MAF Test is that the results are unreliable because of mostly weather and other conditions that affect the heart rate. For example up here in Canada I train in the winter at -20C and in the summer at +20C or more. And even when I try to compare results for only the winter time that still does not work because road conditions are different and running in higher or slippery snow changes the effort level compared to better road conditions making a comparison impossible.

    The whole concept if flawed in my opinion because MAF only uses the heart rate to judge the effort level and that is incorrect. When it is hotter the heart rate goes up because the bodies core temperature is higher and more blood is sent to the skin to provide more cooling. This however does not mean that my muscles are working harder at all. Yes the heart is working harder to provide more cooling and that is a limiting factor for sure as we have a maximum heart rate.

    For the 2 1/2 years that I am training now as a distance runner I have improved as a runner while my heart rate for a given pace has pretty much stayed the same. This really surprised me but the same is true for my wife that is also training for the same time. I was expecting our heart rate to drop for a given pace but that did not happen. Instead I can run faster because I can maintain a much higher heart rate for a much longer period without getting tired. In other words I have gotten stronger.

    Now my observation does not mean that running at a low heart rate is not a good idea. I love this kind of training but I simply did not notice any change in my heart rate for a given pace from the data I collected over the years. I have made a heart rate/pace chart and log every run. Of course the longer the run then tyhe heart rate creeps up as the run lengthens. Maybe my heart rate will decline eventually but I have no idea how many years that will take.

    • Ulrich:

      The heart rate will always coincide with the body’s stress levels. So regardless of why the heart rate is increased (muscle activation, sweating, etc.) the body’s overall stress response to exercise will be the same. And because the stress hormones themselves release and regulate metabolic fuel use (fat and sugar), fat and sugar utilization is tightly linked with heart rate through the hormonal pathway.

      In regards to the magnitude of the change when you start sweating, the skin is the body’s largest organ. Sweating is the biggest use of the skin, meaning that running the sweating system requires a huge energy expenditure. Think of how difficult it is to run while you are digesting a heavy meal: it’s not just blood that the digestive system is demanding. It’s also demanding fuel commensurate to that blood demand. So the skin is demanding even more energy and blood (due to its larger size).

      Because of this, the body is using its stress hormones to release more fuel (as much fat as possible but sugar when its capabilities are exceeded), and the heart rate goes up based on that hormonal activity. In any case, even if the skin wasn’t demanding that much energy and the only reason for the heart rate’s increase is the skin’s blood demand, hormonal activity would still drive the increase, changing the body’s fuel utilization even if the energy demand wasn’t as high (which it is).

      The body has for all intents and purposes 2 different engines: a fat-burning engine and a sugar-burning engine. Because of the relationship of heart rate to stress hormones to fuel utilization, the fat-burning engine is primarily active at a lower fat-burning heart rate and the sugar-burning engine is primarily active at a higher sugar-burning heart rate. If you can run for longer at a higher heart rate it means that your sugar-burning engine in particular is stronger, not that you’re “fitter” across the board. But because your heart rate is higher for longer, your stress hormones are commensurately elevated for longer. This means that regardless of whether you can sustain a certain intensity for longer because a particular engine is more powerful, the weaker fat-burning engine, and the body as a whole (not just that engine) is bathing in stress hormones for that much longer.

      • Ulrich Maier says:

        Thanks Ivan for your explanation that is very interesting. I was just sharing my own observations on heart rate development for myself and for my wife because we have been measuring our heart rate pretty much from the beginning when we started training 2 1/2 years ago.

        In any case when I am running a 10k race my average heart rate is at about 92% of my maximum heart rate at 170 beats per minute. In other words when I like to run a 10k as fast as possible my body is going to consume fat or sugar as it sees fit and since I run as hard as I can probably more sugar. I think that is normal.

        But the interesting question is why I am faster now then when I started training 2 1/2 years ago. The answer to that is that my legs and other parts involved in the running process don’t fatigue as fast as they did before. Sure the heart is pumping blood but it is the legs that do the running. Even in an unfit person the heart is usually the fittest organ because it needs to beat all the time. So the heart is in that case not the limiting factor but it is the legs because after a short while they don’t want to move any more in an untrained person.

        Also I know I am fitter because when I started running I could barely run 10 yards before I had to stop. Then 1 1/2 year later I ran my first half marathon in 2 h 26 min and the same distance two weeks ago at 2 h 13 min. But here is the surprise for myself and what I did not expect is that my heart rate for lets say 6min/km pace did not really come down and has remained in a range of 145-150 beats per minute.

        I would have expected with all the training that I am doing which amounts to 150-250 Km a month of running that I would see a drop in my heart rate for running at 6min/km pace but sadly and disappointingly I did not make that observation. The same observation I have made for my wife her heart rate has not diminished either.

        Maybe the heart will get larger and the heart rate will drop but that might be a process taking years. Maybe in my case the heart did not see any reason to grow because my body thinks that the hearts performance was sufficient. Maybe if I train more interval sessions with my heart rate 180 beats my heart might grow instead of training in lower heart rate zones?

        • Ulrich:

          Thanks for your comment.

          The MAF HR is effectively not a cardiovascular measure. It is a metabolic measure. It predicts the amount of stress hormones at a given heart rate (and therefore the fuel utilization percentages). That’s why the MAF HR is important. It is not about how “fit” the heart is compared to the legs.

          The reason the heart rate doesn’t drop is because you are training your body to run with a certain mixture of metabolic fuel, which corresponds to the heart rate. As long as you don’t teach your body to run with a more fat-oriented mixture of metabolic fuel (produced by fewer stress hormones and a lower heart rate) your heart rate won’t drop. Effectively, you need to approach this problem the other way ’round: run at a lower heart rate to make you body better at running with a more fat-oriented mixture of metabolic fuel (which will allow it to produce and burn more fuel at higher rates while maintaining the same ratios).

          • Ulrich Maier says:

            Thanks again for your info Ivan. Well most of my training is at zone 2 or zone 3. I hardly ever train in zone 4. I love running intervals at 10k race pace but I tend to get injured(calf strain) so I had to back off. Maybe my heart was actually growing but because the stress hormones as you are describing the heart rate is just not coming down.

            The reason why I like to train faster is because slow running is mechanically very different from fast running or race pace running. So when I train slow all the time I find it hard to run fast in a race. So what I tried to do is to run 200m repeats at race pace and in such a short distance my heart rate only rises to about 150 BPM(zone 3) and then comes down very quickly during my 200m walk recovery. Ivan do you think this is this a possible option to reduce the stress hormones? Or run/walk is that a valid option to run faster and then recover during the walking interval?

          • Ulrich:

            Training at race pace is important to be able to achieve your results. But in order to train the system that underpins race performance at the race pace of any event, it’s important to also train at a low intensity, under the aerobic threshold. This is the intensity at which elite 10k runners spend 70-80% of their time training, and eilte marathoners spend over 90% of their time training.

  • Antoine says:

    I did my first MAF Test this week end, and I wonder if I defined my MAF HR correctly, because my pace has been very stable throughout the test : 5:00 min/km (+/- 2 seconds) from km 1 to km 8. I understood that normally at MAF HR, speed should decrease km after km.
    I’m 37 and used the 180 formula to set my MAF HR at 143 (I believed I did not need to modify the number as I don’t really fit in any of the 4 categories). During the test I averaged 141, with variation between 138 and 143 (rarely 144 and above).
    Is that normal or should I tweek my MAF HR ?
    Thanks for the feedback,

  • Josh says:

    Hi guys,

    I’ve been training under MAF hr rules for about 3 months but haven’t seen much change and wondered how low can I expect to go under aerobic speed?

    My first ever MAF test was 4:48/km over 5km (fastest km 4:41)
    My latest one (4 months later) was 4:58/km (fastest km 4:34)

    Basically I don’t seem to be seeing much improvement and wondered if I should intro anerobic excercise to see some further improvement or try sticking with it?

    I’m running between 35-60 km a week.

    Thoughts would be most helpful



  • Becca Boo says:

    I really want to use the app to record my MAF test results but can’t seem to get it to work. It won’t sync with my Garmin heartrate monitor and GPS. Any tips on what I am doing wrong or is the app not compatible with Garmin watches? I have downloaded it on my iPhone but it won’t use the location on there either.

    • Becca:

      We don’t have compatibility with Garmin watches. Typically, Garmin products only play well with other products they co-brand with, which our app doesn’t. Furthermore, most Garmin products carry ANT+ technology, which our app does not have an adaptor for.

      I’d recommend a Bluetooth chest-strap heart rate monitor such as the Suunto Smart Sensor. I use it myself and I’ve never had any problems with it.

  • Andrew says:

    I believe I was first introduced to the MAF180 while reading one of the several books on correcting running form, training, and biomechanics. I read several articles and information on this website and watch a few podcasts by Dr. Phil. It made total sense. I am 41 and in the Military. I am required to complete a 2 mile run in a period time according to age standards. I bought a Garmin vivo active GPS watch and chest HR monitor in January 2017. I was typically running 4 miles everyday at a comfortable pace of approximately 9:00-9:20 min/mile pace. I calculated my max aerobic HR at 145, because 140 was TOO slow for to run at its pace. I started truly trying to be disciplined when running using the my max aerobic HR, in cold weather, and found that I had to run at 11:00 mile pace to keep my HR under 145. It was such a struggle, because I would kick into my normal 9:00-9:20 comfortable pace. My HR would rise above 145 and I would have to slow down. The up and down of my HR was causing me to get frustrated. Simultaneously, I start to adjust my diet and found I was carb dependent. I took the appropriate steps since March to eat the foods described on this site. I have kept a record of my MAF tests, which don’t seem to show anything other than less mileage, slower pace, and still struggling to keep my HR under 145. My diet is good, I wear Altra One 2.5 zero drop and I have been running in Luna sandals Mono Gordos too. The main impact at this point that I think is causing issues are stress and being frustrated going so slow. I was passed on a high school track by a 70 year old man a few weeks ago as I ran an 11:30 pace at my HR (134-144). I have a Fitness test in the next two months and feel like I should get in gear, but I can’t get things figured out. I want to revert to Speed work to get faster, but I don’t want to give on MAF. I bought The Big Book of Endurance Training and Racing and read about 100 pages so far. Do you have any suggestions? Thank you

  • nick says:

    im keen to start this system of training – it is similar to the principles behind 80/20 running by Matt Fitzgerald.

    I would like to get my wife into this. She favours high intensity HIT, spinning etc. Her max HR is way more than mine. me 180 vs her 220ish. we are both 48 yrs old.

    My question – would the 180 formula work for her with the much higher HR?

    thanks Nick

  • Suzanne says:

    I’ve been working on MAF training for about 6 months now and have noticed very little improvement but am determined to keep at it for a while! I have noticed that if I train first thing in the morning (fasted), I am completely unable to jog. My heart rate tends to reach my MAF limit just through brisk walking. However, later in the day, I can usually jog very slowly for at least part of the training session. The only reason I can think of for this is that perhaps it is related to cortisol being highest in the morning. Any thoughts? Am I better to avoid morning training and try to focus on afternoon/evening MAF training?

    Thanks for all of the great information!

  • Ryan C. Ashton says:


    You talk about doing the test at “low to moderate intensity”. What exactly does that mean – in tiers of heart rate? Does it mean that I must do it at my MAF HR? Or lower? Or higher?



  • Patrick H says:

    So when doing the MAF test and my HR goes above where it should be, should I walk/slow down until it gets in range and then continue. I have tried this once or twice, but get a little frustrated when I suddenly bounce over the zone.

  • mike brown says:

    I am sure you have covered this but can’t find any reference to this. I have been working on my run cadence as I realized my cadence had dropped to around 160-165 over the winter. I started running back with my metronone set at 180 and noticed how much better my legs felt and nagging aches disappeared. Unfortunately, my HR also went up with the cadence increase to the 177-180 range. I am not considerably short of breath, but there is an increase in my heart rate, especially on hills of about 5+ BPM. When I am doing these runs I am finding it difficult to keep my cadence up at the low HR. I am 51 with years of endurance training/racing. So my HR would be 134. My previous aerobic zone was 138-147. Easy run/recovery pace was <138. From a run mechanics standpoint, should I continue to keep my cadence at 175-180 and do you have run mechanic advice to offer to maintain HR at 134? Is this the HR I am to use for the progress test?

  • Simon Mottershead says:

    I have struggled to do the MAF test as my HR monitor (Garmin) wont link with the app. I think the App is excellent apart from one small issue that makes it unusable for me. I do not run with my phone but rather with a Garmin watch and HR monitor – it would be 5 star excellent if the App linked with something like Garmin Connect or Strava so that the data could be transferred after the run from the watch to the app. As it stands even if i ran with my phone as the app cannot find my HR monitor i would be none the wiser.
    As I say I think the app is really good but without being able to transfer the data – and it not finding my HR monitor – a lot of the critical functionality for the test is lost.
    Thank you for the website, which is tiptop, and all the great information you provide – sorry to be less enthusiastic about the app.

  • Barry Ward says:

    I have difficulty in “believing” the 180-age formula. According to this, all 30 year olds ( with the same health/fitness criteria) would have the same MAF number? BUT – we know that all 30 year olds do not have the same maxHR and hence traditional HR training zones are different for different 30 year olds. So let us say that a particular 30 YO does indeed have a max HR of 220-30=190 and his twin brother has a maxHR of 200 ( 10 higher) . Surely the MAF numbers between the two twin brothers would show a difference of 10 BPM??

    • Barry:

      Two twin brothers may be different, but not on account of MAX HR (we’ll ignore the fact that someone’s absolute MAX HR is almost always genetic, and as such, unlikely to be different between twins). MAX HR is, in a simplified sense, how hard the heart can pump without bursting. The MAF HR tells you, based on your muscle fiber distribution/activation levels, at which intensity your body starts producing lactate.

      So this is related to the heart rate in the sense that a higher intensity means both a higher heart rate and more activation of the aerobic (Type I) muscle fibers. (After all the Type I fibers become activated, the body needs Type II fibers, and that’s when lactate levels start to rise.) So the genetics and epigenetics that inform what the heart is capable of and what the muscles are capable of are 2 different sets of genes. In other words, it’s possible to have:

      1) a very powerful, very trainable heart (and thus a very high MAX heart rate) but a very weak aerobic system in genotypic terms.
      2) a very weak, very untrainable heart (and thus a lower MAX HR) but a very powerful aerobic system, and thus a much higher MAF HR.
      3) a genetically very weak/not very trainable heart AND very weak/not very trainable aerobic system (low MAX HR and low MAF HR)
      4) a genetically very powerful/trainable AND very powerful/trainable aerobic system (high MAX HR and high MAF HR).

      Hope this helps.

  • Carolina says:


  • Carolina says:

    I didn’t think I would enjoy training at my aerobic heart rate….but it’s slowing me down and I’m finding new sights to see during my regular trail runs.
    Do I follow the training plan I’m currently using as far as mileage but training at my MAF heart rate? Exclude speed training? Will start Training for a summer trail marathon and 50k. Races this spring on trail-several 5 milers and a cou Le of 1/2 marathon trail races.

    • Carolina:

      That’s the safest option.

      What we usually suggest to people is to train only aerobically until they have 3 consecutive months of improvement (not just “training”) at an aerobic heart rate. It’s not the case that this is necessary for absolutely everyone, but rather that it is a way to be pretty sure that your aerobic system is powerful enough to tolerate some anaerobic training and racing.

      So it’s not necessary to completely eliminate your anaerobic training if you have races ahead, but it will slow down your aerobic development.

  • tomas v says:

    Im 32 years old and been running for 4 years actively now. Planning to do a 3k version of the maf test. My question is regarding initial heart rate inmediately starting the test, how quick into the test should I aim to get into the heart rate zone (180-age)?

  • Fiona Cameron says:

    Hi Ivan,

    I have struggled with getting a consistently good HR reading from my TomTom watch, but I have been trying nose breathing for a few runs. I find that my pace is close to what I am doing at my MAF HR ( when my HR does stay down) but my HR can be 10bpm higher than my 180-age MAF HR of 125. Does that suggest that the 180 formula is a bit off for me?
    What I like about nose breathing is that I can feel that l am belly breathing in a way that l am not when l mouth breathe.

    Thank you for still monitoring this thread. I was pleased to come across the comment and reference to Mark Wisdom’s book, but I am a bit late to the conversation!

  • Jim H. says:

    I am 60 years old. Male. I have run approx. 55 foot races in the last 8-9 years (5 half marathons with ever-improving times were the pinnacle lengths); half my races were trail races through Georgia mountain/hill country. Recently, to combat knee & hip issues—or as I like to say, “to spread the pain” 😉 I started training for Sprint Triathlons and have completed 2 successfully. I keep careful training records with a heartrate monitor & GPS and try to keep at least 80-90% of my run & bike training in the aerobic range per the MAF method—though here, in the warmer months, that sometimes means walking uphill.

    I have some observations/questions:

    1) I live in Atlanta where the runners’ motto is “Heat Hills Humidity”. I’ve noticed that, no matter how far along in my training I am, when the humidity & heat goes up, my MAF test times increase. I am faster at 60º & 50% rel. humidity than at 85º & 75% rel. humidity—given the same heartrate & same course (even on the treadmill). My question is: how can one compensate/account for this when taking MAF tests?

    2) A significant percentage of my training is barefoot running. Again, at the same heartrate, my barefoot times are slower than shod times over the same course (given the same temp. & rel. humidity conditions). How does one account for this in testing, training, etc.?

    3) At my anaerobic threshhold, because of my age & the hills & humidity issues, it is impossible to train my fast-twitch racing muscles. For example, full leg extension behind me is impossible to achieve at aerobic rate. I am able to accelerate downhill, but barefoot running form calls for a shorter stride, higher knee in front. This is a complicated question that may be beyond the scope of this forum. In other words, MAF Method heartrate training is often at odds with Barefoot-style running where most of the concentration is on form, & I have trouble reconciling the two.

    4) Lastly, what is the best method of monitoring heartrate while swimming? My Garmin is not waterproof & I’m not sure the chest strap would stay on even if it were.

    Thanks for all the great information!

    • Jim:

      Thanks for your comment.

      Let me answer in sequence.

      1 and 2) Your best bet is to take your monthly MAF tests in a climate-controlled environment such as a gym throughout the year, on a treadmill. While you won’t be able to usefully compare your treadmill speed to your road speed (or your unshod speed to your shod speed), comparing treadmill speeds will correctly track your aerobic development. It’s also important to note that the aerobic engine doesn’t change from shod to barefoot running: you are still running with the same machinery, and as long as you train under your aerobic threshold, you are still developing that machinery at the same rate. But barefoot running uses more energy (for good reasons) than shod running, and your speeds will reflect that.

      3) I want to make sure that we’re separating the anaerobic and aerobic thresholds. At the aerobic threshold is where the maximum rate of fat-burning occurs. Just beyond it is when anaerobic function begins, meaning that lactate production begins. At the anaerobic threshold is when enough lactate is being produced that it outpaces the body’s ability to process it. Which brings me to my point: Type II fibers begin to be engaged immediately above the aerobic threshold (because they are the main lactate producers). If you are running at the anaerobic threshold, your Type II fibers are already activated in force, regardless of speed or slope.

      So the activation of fiber type is NOT dependent on speed, stride rate, stride length, or degree of extension. It happens that Type II Fibers become active at high speeds and stride rates, long stride lengths, and full extension, but because this typically requires a very high degree of metabolic activity to produce. So activation of fiber type is far more correlated to the metabolic threshold at which you’re working: if you are at or below your aerobic threshold, you are working overwhelmingly with Type I fibers. If you are at your anaerobic threshold, you are using all of your Type I fibers and most of your Type IIa fibers. By the time you are above your anaerobic threshold, you are using all of your Type I fibers and Type IIa fibers, and most of your Type IIb Fibers.

      This bring us to one of the main points of MAF Training: to run WITHOUT activating a significant amount of Type II fibers, so that the body learns how to do the majority of the work with Type I fibers. Because Type I fibers are primarily responsible for burning fats (and Type II fibers only burn sugars), your fat-burning capability resides squarely on your ability to run using primarily Type I fibers.

      4) There are some waterproof heart rate monitors and watches, but those are typically on the very high end of price ranges.

  • Laura says:

    Hi, I understand almost everything and i am thrilled to be in my 4th week of high fat/protein, following recipes and engaging in MAF. But i have one nagging question. While i hope i make great strides with MAF (i’m preparing for Chicago and NYC fall 2016 marathons) i dont understand how i will be able to ever run a full marathon or even race a 5K without going into an anaerobic state. I do understand that my MAF will improve and this in turn will also have positive impact on my anaerobic system over time. But is the general rule of thumb that you can race mostly in an anaerobic state whether its 20 minutes or 3 hours? If i want to run say a 3:30 marathon at an average 8:15 pace but my MAF is finally at an 8:30 pace (which its not yet i’m still at 9:45 and slow running/jogging) can i still attempt my 3:30 marathon knowing i will be running 26.2 in an anaerobic state? Additionally lets say in a year i make incredible improvements and i go from my original 10:15 MAF to a 7:15 MAF and i settle there but i want to run a 20 minute 5K? how would this ever be possible without being in a total anaerobic state? I am mostly concerned about my upcoming marathons (and even ones in the future if i never reach a MAF number that is equivalent to my Marathon goal time (my PR right now is 3:38 (which i accomplished before starting on Phill’s program) and my current MAF is 137 approx a 9:45 pace. How can i possibly run Chicago in 5 weeks time at a 3:35 pace and remain below my Max heartrate?


    • Laura:

      Running 15 seconds faster than your MAF HR is an anaerobic state in the sense that there is some (read: very little) anaerobic function. This means that you are running in a state at which you are exerting your body’s systems to some extent and creating some by-products, but that is just fine—you’re racing. To put it more explicitly, at 15 seconds faster than MAF, you are still running overwhelmingly aerobically, but not completely. The important part is that you allow yourself to recover from this anaerobic exertion with a period of aerobic training.

      Going above your MAF HR is not a bad thing. Going above it allows you to train and use the systems that burn sugar. The problem occurs when people train enough above their MAF HR that those sugar-burning systems become far more powerful than their fat-burning systems. The other problem is that this is typically the rule among runners and other exercise enthusiasts. So, as long as your body is protected from this (by having a powerful aerobic system), it’s just fine to go above your MAF HR for bits of anaerobic training, and racing. For example, we discuss in this article how running 15 seconds faster than your 1st mile MAF HR is a marathon race pace that typically works very well for people of a huge range of speeds.

  • Graham Leck says:

    Is there a minimum amount of work that should be done at each session.
    I have been using a Concept 2 rower doing 5k and an assault bike for 10K.
    Is this sufficient or should I be doing these distances several times in the same train period with a set rest period.
    I have already noticed that my times are improving while still working at the same HR.
    I have also noticed the major effect that doing a Crossfit workout prior to doing MAF training increases my times.

  • Jim Roche says:

    I was wondering about the progress on the MAF test if you are over trained. I have been over training for approximately 2 years. My marathon time fell from 3:05 to 4:05. My 5K time fell from a 18:30 to a 22:30. I am proceeding on a 60% reduction in mileage and all aerobic running. I would like to see progress. Since I am over trained, will it take longer to see any progress on the MAF test?

    • Jim:

      It’s very likely. What you should see when you start training aerobically is that either your speed increases, your symptoms of overtraining abate, or both. Usually, in my experience, when people are ill, injured, or overtrained, the disappearance of symptoms heralds an increase in speed in the near future, but rarely the other way around.

  • stephen says:

    Hello Ivan,

    I am 38 years old and have always been very fit but have been taught to train with close to maximum intensity at almost all times. My sessions would almost always be interval in nature.

    Last year I had open heart surgery to repair a leaking Aorta Valve. During my recovery I have been pushing myself as hard as I have historically [doing intervals] but have noticed my heart rate has been at much higher levels than before. This brought me to MAF as I am aware now that my aerobic function has all but gone after such a long time.

    I do not run but I row, kayak and cycle with regularity. I have calculated my MAF as 180-38[age]-10[for heart surgery] so am attempting to train at between 122 – 132. Like others I find it very slow but am enjoying the difference in feeling/recovery to the general feeling of exhaustion when I used to exercise.

    My question relates to the upper limit. How strict is this limit? For instance when I cycle I may encounter a rise in gradient that even at a very slow pace I struggle to keep my HR below the limit? Overall my average HR for the ride would be within the acceptable range [say 130] I might be spending 5%- 10% of my time above my upper limit? Is this fine?


  • cindy says:

    Hello Ivan,
    I have been doing MAF for 2.5 months now and love it. My MAF HR is 130, and I find my most comfortable pace (and the most effortless to maintain) is 133 BPM. My question is 2-fold: Firstly, I”m assuming it’s fine for my HR to go below MAF, such as when I’m riding my bike on a downhill and can’t apply enough force to keep my HR in the MAF range, but wondered if these cyclic decreases interfere with fitness gains of the aerobic training. I usually ride for 90-120 minutes and my HR is below MAF maybe 10-15% of that time. (it is much easier to maintain MAF when I run but I try to do more biking to save my knees) The second part of my question is this: when biking for my aerobic workout, many times on uphills, my HR will go to 140-150 and I try and get it down as soon as I can. I’m wondering if this (also cyclic) intermittent rise in HR can count towards my higher intensity training (MAF definition) as it accounts for less than 15% of total workout time, or does the higher intensity training need to be continuous to reap benefit or does it negate progress?

    In general, following the protocol described above, my fitness and aerobic capacity has improved markedly and I feel more fit than I ever did following Mercola’s HIIT (my target HR was 164) . So much so in fact that I don’t even do HIIT anymore, for me it led to OTS which I will never flirt with again! Also as a medically trained person who has done a ton of research, I feel the MAF science makes so much more sense than HIIT.

    thanks so much for your time and thoughtful reply,

    • Cindy:

      Thanks for commenting.

      Generally, those decreases don’t matter. Anything below the aerobic threshold will give you important aerobic adaptations. Even walking for a few hours is an excellent aerobic exercise. While, of course, walking 20-30 BPM under the MAF HR doesn’t give you speed adaptations at the MAF HR, it does develop a lot of the infrastructure that the running movement utilizes.

      In terms of going over the MAF HR during aerobic workouts, I’d advise against it. Imagine that your body is a child that is always asking “how does my parent want me to adapt?” If enough of your “aerobic” training is anaerobic that your body concludes that its adaptation should mostly be anaerobic, then it’ll do that. So, it’s very important that, during workouts that are intended to be aerobic, you err on falling far below the aerobic threshold (as you do down hills) instead of erring by going above it.

      There are many different kinds of high-intensity training. Interval training can be as beneficial as steady-state lactate threshold training, for example, although they produce different adaptations.

  • RonG says:

    Okay, it’s been a little over a month now of doing MAF, and here is where I am at I’ve done two different 3x1600m MAF tests in the last few days, one super slow jogging (HR 130) and one walking (HR 128) with the following results:

    Walk Run
    1 12:36 13:45
    2 12:47 14:42
    3 12:52 15:11

    I’ve been running fairly consistently over the last few years. I have a true MAF of 128, but I guess I could stretch it to +5 by definition. I can’t really run much lower than 130, even at that speed my gait is pretty messed up and I feel it the next morning. When I walk at MAF I am close to max speed, but probably still have another 30-45 seconds in the tank when I hit MAF. I currently run 6 days a week 90 to 240 minutes, all MAF. I started a 24 week training cycle for a 50 mile trail race in September this past week. I have a trail HM in 3 weeks and a 50K race in July, both of which I am just using at training runs more than actual races.

    I had my first long run on Saturday (12 miler) and it took me just under 3 hours to complete at MAF. About 65% of this was walking in order to stay under MAF. I’m kind of in a quandary about where to go with it now that I have started training. I don’t mind mixing in walking since I certainly do my fair share of it in a 50 mile race. Should I continue to walk exclusively and at some point I either max out my speed and then I’ll have to make the jump to running to get to MAF and essentially start over with super slow pacing? I guess I should mostly be concerned with time on my feet more than distance but I am covering 40+ miles per week so I’m getting in my requisite mileage, it’s just taking me much longer to do it. Should I split my long run day into multiple sessions? At this pace, for a 20+ miler, I’ll be at it all day. Can you effectively train for a race walking and then lace them up and start running on race morning?

  • RonG says:

    Another think I am unsure about is the warmup. I have run across several comments about not warming up properly but I really haven’t seen what you consider a proper warmup. If my upper limit is 128, where should I be for the first warmup mile? I try to hit around 115ish. Is that too high or low? I notice if my warmup is up in the low 120’s then I can’t keep it in range very well when I try and switch to running.

    • RonG:

      That shouldn’t be a problem

      • RonG says:

        Ivan, A couple of other things came to mind. What is the minimum time each workout should be for base building. I read something by Mark Allen that I thought said a minimum of 75-90 minutes was necessary to gain any real aerobic benefits from the run. Is there a point in time where you don’t gain any more benefit or at least it is outweighed by increased injury potential? Second, I have a MAF of 128. I try and stay as close to this as possible. Trying to constantly check my HR on my watch throws off my gait so I do from time to time see that it creeps to 129, maybe 130 on occasion so I slow down and it immediately comes back down under 128. I know 128 is the magic number, so I was wondering at what point does the run get ruined aerobically if you go over the MAF number? In a typical 6 mile run I may spend 30-60 seconds at 129-130. Is this hindering any aerobic benefits I am trying to gain?

        • RonG:

          That’s not really the case. For example, an old, sedentary person can experience major health gains by walking only a few minutes a day. They are making those gains because their aerobic base is improving. My point is that your aerobic base gains will be a product of how much more you are aerobic training than before. If you’ve never trained aerobically, you’ll make gains with only 15 minutes. That said, your physiology will probably be tolerant of a lot more, so it’s fine to start with 30 or 45 minutes with most people.

          Myself, I train 4 times a week for 60 MAF minutes bookended with 15 minutes of warm-up and cool-down (for a total of 90), plus one long run of 90+ MAF minutes also bookended. This is equivalent to about 55 miles/week at present. It’s quite enough for me to make aerobic gains.

          Usually, you start to see diminishing returns past the 2 hour mark of constant activity, just about across the board. This means that for an ultrarunner who is training for a long event, 2 or 3 different 2-hour workouts a day will have a much greater effect on their physiology than one 6-hour workout. These diminishing returns occur because of increased stress, which increase the risk of injury.

          One cumulative minute over MAF changes just about nothing in the training response. Let me put it to you this way: aerobic training isn’t a mysterious and arcane process. It’s the most natural thing in the world. If you go on a long, leisurely birdwatching hike, and you do one lone sprint around a bend to catch sight of a golden eagle spreading its wings, for all intents and purposes, it is still a long, leisurely hike.

          The greatest runners in the world became what they are by jogging as a form of transportation. They weren’t worrying about staying under the MAF HR. (Also the point is that they weren’t worrying about going fast all the time either). Another example: go on a 1,000 mile hike (like the Pacific Crest Trail) and you’ll end up with a gargantuan aerobic base, despite not having thought about your heart rate even once.

          Hope this helps.

  • Bob says:

    Hello Ivan,

    Two questions:

    1) Is it possible to overtrain while maintaining <= MAF heartrate? That is, can I put in too many hours at this rate and actually hurt my progress? Or does the heart rate just naturally force me to slow down and stay safe no matter how many hours I do?

    2) Is it safe to stay off carbs for much longer than two weeks? I am on my third week since starting the TW test and I like how I feel and where my body is heading.

    Thank you, this web site which shares the work you and Dr. Maffetone are doing is changing my life..


    • Bob:

      1) If you took it to the logical extreme, you’d find that you’d only be able to walk, and then only be able to sit, and then only be able to stay awake at the MAF HR until you’re forced to sleep, 23 days later. In other words, the MAF HR regulates your metabolism at a low relative intensity, but the absolute exercise value that low relative intensity corresponds to does fall (which is why the first miles in an MAF test are faster than the last). My extreme example above is a continuation of this, essentially. Suffice it to say that MAF training is exercise from which you have to recover in order to become better. For most people, 5 hours a week of MAF work is a LOT.

      2) The best easy measure of whether something is good for you is whether you feel “well” in a very broad sense: if you have good energy and a brisk step and great digestion and good sleep and good heart rate variability (for example), there is a very, very low chance that what you’re doing is bad for you. But if there are a couple of nagging symptoms that seem to be slowly creeping upward, there’s probably something negative going on. That said, there’s no reason why in principle someone simply can’t be healthy on a very low-carb diet.

      You’re very welcome.

  • RonG says:

    For background information, I am 52 years old and last year I completed two sub-4 hour marathons and one 50 mile mountain trail race. I am attempting to do the MAF training, using 128 bpm as my upper limit. I am doing 90 minutes 5-6 days per week 3 weeks into the program. The problem I am having is that I can’t run basically at all and keep my HR under that target. I can only manage a fairly brisk walk (14:00 miles). If I attempt to jog even more slowly than that walking pace my HR jumps to the mid to upper 130’s in seconds. I have a hard time believing that my aerobic fitness is this awful.

    • Ron G:

      Your heart rate at a low speed is a direct indicator of your aerobic function.

      The reason it jumps like that is due to dominance of the sympathetic nervous system during exercise (which is a hallmark of anaerobic function). The sympathetic nervous system is what helps the stress response kick in. When someone is more aerobically developed, they have, among other things, a very powerful parasympathetic nervous system, which is the system that helps calm the body down. The hormones that calm the body are also those responsible for burning fats, dilating the body’s air ducts and blood vessels, and allowing for effective transportation of gases and nutrients to the muscles.

      If your heart rate jumps, it’s because your body either doesn’t have powerful delivery systems for oxygen and fats, or it’s too stressed out to use the parasympathetic nervous system and activate them. In other words, it is a direct indicator that your aerobic system is either malfunctioning (or more likely) not very powerful.

      • Val says:

        I have been following a no sugar, no carb diet for 3 weeks now and seeing great results, however I am seeing a similar situation as Ron G. I am 55 years old and have been running since I was in middle school, 13 years old as a miler and then marathons and now Olympic Tri’s. I love running and it is an important part of my life and would like to continue for years to come which is why I am so interested in the MAF method. My MAF puts me at 125 max bpm (15:25/mi avg) which is a walk and not a run at all. If I start to jog I will be over my max bpm.
        Any advice? Any additional testing I can do to determine if it is my system for oxygen and fats or my parasympathetic nervous system? My resting heart rate is in the high 60’s and I do meditate too, take magnesium
        (600 mcg), Zinc (6.75mg) and B1(1.4mg), B2(1.7mg), B3 (12mg), B5 (10mg), B6 (2mg), B12 (100mcg).

        • Val:

          Sure. Go to an exercise lab and take a Fat MAX test (heart rate at maximum rate of fat-burning). Both systems you mention (the autonomic nervous system and the aerobic system) have a very close correspondence to each other. For example, if you start burning more carbs and less fats, you’re also using the sympathetic nervous system (which is what drives that change).

          What I recommend is to run one day a week at a pace of your choosing (shorter distance if faster, longer if slower), and the rest of the time walk at the MAF HR. One of the things that the MAF HR helps you do is develop parasympathetic tone so that you can have a higher level of sympathetic activity without the sympathetic nervous system taking over (read: without sugar-burning becoming rapidly dominant and suppressing fat-burning). Simply put, unless the 180-Formula is grossly misestimating your MAF HR (which is why I suggest the Fat MAX test), walking is at present the point where you are in sympathetic/parasympathetic balance, and training your fat-burning system the most.

      • RonG says:

        Okay, after a couple of weeks here is where I’m at. I have two choices and I’m not sure which one is more beneficial so I’m hoping you can help. The first option is that I can just maintain a brisk walk and keep my HR in the 126-128 range. The other option is I find that I can walk a mile to warm up at about 116 bpm, then I can alternate what I will embarrassingly call a jog taking my HR up to 126 and then walking it back down to 122-124. I can usually get about 40, maybe 50 meters before having to walk. The problem is my pacing is all over the map. If I analyze my last few sessions, mile 3 is higher than mile 2 (mile 1 of the MAF), and then miles 4 and 5 see my pace actually go down from mile 3’s pace. From what I gather my pace should continually rise as the miles continue. I can only assume this is because of the walk/run mix. I may not be able to get accurate numbers until I can “jog” the whole test, whenever that may be. It seems that getting at least a modicum of running in has to be better than just walking but I’m clearly no expert.

        • RonG:

          If walking takes you close enough to your MAF HR (128 BPM as I remember), then stick to walking for the MAF Test as well as the rest of your MAF training. But walking by itself won’t get you running. So here’s what I suggest.

          Unless you are ill, injured, or overtrained (or recovering from any of these) do the following:

          Every 2-3 MAF sessions (which means essentially every 2-3 days), do one running session at your preferred speed, making absolutely sure that you finish the workout completely fatigue-free, feeling “refreshed,” “restored,” or a comparable adjective. This session will be around 1/2 the time of your MAF session. So, for every 2-3 hours you walk, you’ll run for 30 minutes.

          Also, take up jumping rope, even if you only do it for 5 minutes at a time. I recommend doing this 5 days a week. While jumping rope may take your heart rate above MAF, it certainly won’t bring it even close to your heart rate while running. The reason for this is because jumping rope mimics the vertical movement of running (and training your body to be resilient to the stress associated with vertical impact) while omitting any horizontal movement and the stresses associated with it. While it is important for runners to minimize their up-down movement, getting better at jumping rope also means minimizing movement (and increasing speed) which only helps you for running. So, jumping rope is an opportunity to train the critical part of the running gait (midstance, also known as the running pose) while keeping the heart rate at a decidedly lower level than you ever could running.

          And to train this even further, once you become good at jumping rope, start jumping on one leg. To do so correctly, bring your other foot up and gently touch the heel against the knee, and keep it there. Practicing that alignment—with the foot level with the knee (and the hip above it), as opposed to hanging back somewhere behind the body—will further improve your running form.

  • Srinivas says:

    I would like to know whether body fat% has any relavence to the MAF pace. I had been at 17% fat level but due some weight gain, it is now at 21%. MAF pace also has dropped considerably despite most of my runs being below the MAF threshhold.

    • Srinivas:

      Not really. Do you mean that your speed has increased?

      • Srinivash says:

        No. My MAF pace has dropped from previous 11 mins per mile to around 12:30 mins/mile. Is this due to added weight of around 4 kgs over a period of last 4-5 months? . My current body fat% is 21% compared to 17% earlier.
        My question is if i reduce my fat % to 10-12%, using other methods such as interval training or strength workouts and with proper nutrition, will this help me in increasing the MAF pace?

        In other words, is MAF pace is directly co-related to athletes body fat %?. I know that many elite athletes have lower body fat % in the range of 6-8% or even lower.

        • Srinivash:

          Not at all. VO2 Max, for example, would influence MAF pace an order of magnitude more than %body fat. The athletes who have 6-8% body fat don’t have that speed because of their lack of body fat. Their lack of body fat is due to their aerobic power. To use a different example, power athletes with very low body fat would have a very slow MAF pace.

          How are the seasons where you live?

  • Christy says:

    Hi… just curious what is normal expected improvement. For example, I am a few months into MAF training, and I am training at an average of 13:00 MAF pace. How long until I am at 12:00 MAF pace?? Thanks!!

  • Michael says:

    I first used the 180 formula 7 years ago with at 135bpm (age 21) and got down to 5:50miles. I know this method can work. Could you please list troubleshooting tips once you begin to plateau. What are the limiting factors for perpetual improvement in healthy runner? Or better yet for steady/linear progress in a healthy runner?

    • Michael:

      Physiology, for one. While VO2 max increases with training, each of us has a different upper limit to VO2 max. So, for example, someone with an upper limit of 90 will be able to keep getting faster and faster for longer than someone with an upper limit of 75.

      The issue is this: after these 2 people have been doing the same kind of aerobic training for a while the person with the upper limit of 75 may see the person with 90 start to leave them behind, and say “I need to start doing anaerobic training to catch up!”

      This is exactly the wrong answer, for reasons you are no doubt well acquainted with.

      However, there are plenty of reasons people plateau that have nothing to do with their physiological upper limits: left-right muscle imbalances in runners, a lack of flexibility, a lack of strength, a very stressful lifestyle, bad nutrition. Resolving any such problems will help us increase the baseline aerobic function of our bodies, essentially increasing the trainability of the aerobic system.

      Another issue is that for distance runners, their aerobic systems are sometimes powerful enough that they can feed energy to their muscles at a rate that closely matches or exceeds their muscles’ total contractile power. (You see this in ultrarunners who can run a hundred miles but are only marginally faster at the quarter mile). At an aerobic heart rate these runners are exhibiting a very high perceived effort.

      The point is that a very high perceived effort can be a stressor itself, reducing aerobic function and essentially becoming a bottleneck to development. The intervention in this case is to increase muscle power so that a person can run aerobically at a lower perceived effort (resulting in lower stress). This basically “opens up” room for the aerobic system to grow.

      Usually, I do this in two-week microcycles. The first “power” microcycle is 25-30% strength/power (anaerobic) + 70-75% aerobic, and the second “endurance” microcycle is 0-5% anaerobic and 95-100% aerobic.

      I hope this helps. Feel free to shoot back with any specific questions or requests for clarification.

  • SimonM says:

    Jacek – I have the same problem. My monitor sometimes shows me HR that would kill me :). I agree with David – it is a monitor malfunction. I’ve had this with several different models of Garmins. Happens whether the strap is moistened or not. The only way I’ve found to deal with it is to switch everything on well before I start running – like as soon as I start changing into running gear and THEN start with a walk and v slow jog and only gradually pick it up. It’s as if the monitor needs a warm-up to settle down.

    Btw, does anyone know of an HR monitor that will give MEAN HR rather than average? I know I can work it out if I upload data and look at a graph, but that’s not always convenient.

    • Simon:

      The mean is the average. Do you mean the median heart rate?

      • SimonM says:

        Ivan – I am mathematically challenged, so I had to resort to Google for this one. It turns out that what I am looking for is the “mode”; that is, the number that occurs most often in a series.

        For HR doing Maffetone, this would be of more use, I think, as average/mean includes times when you are walking to let the HR get back down from “alarm” levels. So we end up with a falsely low number at the end of the “run”.

        • Simon:

          That’s interesting—I’ve certainly wanted that myself.

          That said, I think that your heart rate monitor is averaging every reading it took, not every number at which your heart rate fell. In other words, the average looks a lot more like the mode than you might think: if your monitor took 5,000 readings over the course of a run, and 4800 of those were just below your MAF HR, the average of those 5,000 readings will look a lot like your MAF HR.

          Finally, I wouldn’t worry about that—your heart rate monitor is only telling you about the readings it took. Your aerobic power is what it is, regardless of whether your heart rate statistics represent it to 100% or to 95%. Come race day, what matters is our aerobic engine, not our heart rate statistics.

  • Howard says:

    On repeated MAF tests, how do you know that you are running at the same effort as in previous tests? Are you just staying at the same heart rate as before but seeing if you run faster? And what exactly is the mechanism by which running at a slow rate improves speed. It seems that almost all other training methods recommend some speed training, whether it be a tempo run or interval training to increase speed. Actually I would be quite happy to slow down if I know it will work.
    Thanks for this informative site and for answers to the questions.

    • Howard:

      I’ve written extensively on this topic in other comment threads, particularly the “big 5 articles” in the method section. But I’ll try to answer your question briefly.

      Your perceived effort and your metabolic effort are two different things: your perceived effort tells you how much of your total muscle power you are using, and your metabolic effort tells you how much of your ability to produce energy you are using. So, let me give you 2 examples, to illustrate what I mean.

      Usain Bolt has extremely powerful muscles: at 50% of his maximum effort, he can go a lot faster than me at my maximum effort. But his metabolism isn’t good at continuing to produce energy for a long time—If he and I were to run at my favorite speed, I’d be able to run for far longer than he can: he would be running at a pace that feels “low effort” to him, but at some point (probably before he’s even run a mile) he’d already be feeling like he wants to stop. Even if this pace would feel “high effort” to me, I’d be able to hold it 6 or 7 or 10 miles—because my metabolism is much more powerful, relative to my total muscle power than Usain Bolt’s metabolism.

      Usain Bolt’s heart rate would start going through the roof after this mile. He would feel his run get more and more effortful, but not that much more, because even when his metabolism is producing as much energy as it can, this is a relatively modest rate of production, relative to the rate at which his muscles are capable of consuming energy.

      In short: perceived effort tells you about your muscle power, heart rate tells you about your metabolic power.

      What does this mean?

      Well, aerobic training is essentially about training your metabolism. So, effort doesn’t really tell you much. In fact, as people get better and better at training aerobically, they see their effort go up, their speed go up, but their heart rate stay the same: because their metabolism is getting more and more powerful, it is starting to use more and more of their total muscle power. However, since the metabolism is being used at the same rate, relative to its own total power, heart rate remains the same.

      This is why you see Mark Allen, for example, go from running 9:30 minute miles to 5:45 minute miles at the MAF heart rate, but at a far greater perceived effort.

      This ties into your question about whether “running slow” improves speed. It’s not “running slow” that improves speed. If you want to improve speed at all costs, it’s better to just go do track intervals all day long for two weeks. You’ll see that you become faster more quickly than anyone else. The problem is that your body—specifically, your aerobic base—won’t be able to sustain that rate of development, or that magnitude of development (or, as is usually the case, both), and you’ll see your health collapse, and your athletic ability deteriorate.

      So, the first and most important thing that you’re buying by training aerobically isn’t speed. You can get that elsewhere more quickly. What you’re buying is the infrastructure (aerobic base) necessary to keep speed gains that you make. And you can make huge speed gains by training only aerobically: Since aerobic training is essentially training the rate at which you can provide energy to your muscles over the long-term, more aerobic training means more speed.

      That said, if you have a robust aerobic base and you do choose to do anaerobic training (because you are a weightlifter or a middle distance runner, say), then your body becomes much more capable of keeping those power gains.

      A final point about “running slow”: Mark Allen’s 5:45 min/mi MAF pace (at the height of his career) is blindingly fast. Were he to run “slow,” his aerobic base wouldn’t develop further. While for the majority of us “running MAF” coincides with “running slow” doesn’t mean that “Running MAF” means “running slow.” What we’re asking people is, whatever the power of their aerobic base, to run at a heart rate (MAF) that coincides with an exclusively aerobic utilization of energy. To run aerobically, some people need to start “slow.” But for other people—namely some ultrarunners that Dr. Maffetone has coached—running MAF sometimes means running far faster than they’re used to.

      I hope this answers your questions. Please don’t hesitate to comment back with requests for clarification or further questions.

      • SimonM says:

        Ivan – I think your reply to Howard is one of the most important things written on Dr Phil’s method.
        It should be a “sticky” or something.
        (Btw, the new website is great, but it is difficult to track things without the organisation by topics that we used to have in the old forums. For example, I can’t find any more on this in the big 5 you mention.)

        I may have missed it in Phil’s books and previous efforts to enlighten on the old site, but the distinction between muscle power and metabolic power is very cool – and new to me.

        Apart from the geek factor, it PRACTICALLY important and inspirational. Because as we all know, the beginning of this style of training can be SO frustrating. Having to “run” so slowly, having to walk up the slightest “hill” – I mean I discovered uphill sections of some of my routes that I never even KNEW were uphill! So, you are giving us light at the end of the tunnel. No, I don’t have to keep running slowly. I’m going to have to, eventually, put more effort (increased RPE) into it just to hit the target heart rate.

        In fact I’ve already started seeing this after four weeks – did a 4-miler at average 9:00 compared to first mile of previous MAF test being 9:14. OK, not startling, but then I looked at average heart rate, and I’d run those 9:00 4 miles TEN beats under my target HR!

        This has nice correlations with Lydiard’s base period: “everyone” thinks his runners were jogging through their ten 100-mile weeks when of course they were getting faster and faster. Mark Allen is a fabulous example of where this can take you. He got down to 5:20 miles from 8:15. But/and that took four months of discipline. He then went an blew away Dave Scott because he could run COMFORTABLY at 6-minute pace “all day”. Love it.

        I recently noticed that the famous Pavel, the man credited with bringing kettlebell training to the West, has also advocated training in what amounts to a Maffetone style. So we can do X-fit, resistance training, whatever, to back up our running and still keep it aerobic.

        • Simon:

          Glad you liked my comment! I’m going to save it so that we can put it up somewhere, as you said. Glad you’ve found it inspirational. Lydiard has some excellent theories about training—they’re very useful. But what Dr. Maffetone has over Lydiard in my opinion is this very fine-tuned theory about the biology behind the training (and how it works and why).

      • Mircea Andrei Ghinea says:

        Ivan, that is a very very interesting cool writing! Great! Thank you very much! Great to learn how things work!
        Best regards,

  • Greg says:

    Maybe some one could help me refine my aerobic thresh hold.

    I am 68 years old.
    My resting heart rate is on the average 52 to 54 sitting, 60 standing.
    I can run very comfortably a 10:00 min mile pace and have tested my heart rate at 127 to 130 at one mile intervals for a six mile run at that pace.

    I used the formula 180 minus 68 + 10+5 (category d) to peg my rate around 127.

    Is this optimal or should I go for a lower hear rate?

    • Greg:

      That should be fine. The most important thing is that your aerobic runs don’t stress you out: insofar as they stress you out, they weren’t aerobic. So, if you find that you are getting stressed or tired, you are probably aiming slightly high.

  • Jacek says:

    When I start my warm up – very easy jogging, my HR jumps to 160-180- or evan above 200. I have regular breath thow and do not feel any fatigue, after about 12-15 minutes keeping same easy pace my HR drops to 120 – 125. I am 45 years old now, run 1 -2 marathons a year ( depends on injuries :-), my PR is 3:15. I train 15 weeks prior to the race, between I train cross fit and do easy runs 2-4 times a week.
    My question is if it is ok to have such high HR during warm up ? With MAF method I start burnig sugar.

    • Jacek:

      The best way to do the warm-up is to go by heart rate: start at 20-25 BPM below MAF and then slowly move up to MAF for a period of 15 minutes.

    • David says:


      I have noticed something similar happens to me. I figured out that it was my heart rate monitor malfunctioning. I noticed if I wet the contacts on the heart rate strap before I start exercising that it doesn’t happen. I’m not saying that it’s true in your case but you said you had regular breath and you didn’t feel any fatigue. So this may be something to try.

    • Geoff says:


      At 46, it sounds like you and I are custom built training partners. On the subject, I agree with David. I ignored HR for a long time, taking the “if it hurts, don’t do it” approach. I found myself getting less disciplined over time, doing far too many tempo miles and actually craving speed work. My boss called me a “speed freak”. Returning to monitoring and learning/applying MAF principles, I experienced exactly what you described on my first run using Garmin 220 with chest strap. I wet the strap (realizing I had forgotten) and I spent the next 30 minutes inching my way from 120 to 145. Can’t be 100% sure the water was the fix, but it hasn’t happened in the runs since. Happy New Year!

  • Rodney says:

    I’m currently training for my 4th 100 mile ultra run and have started to do the MAF training, but I’m curious if I should look at doing the test for longer distances (maybe 15-20 runs) and if it should be on level terrain? The race will be on 100% trails.

    • Rodney:

      The development of your ability to burn fats (fat metabolism) is a function of your heart rate. So your MAF training won’t be affected as long as you stay in the same heart rate. That said, for sports specificity (fat-burning aside) it’s a really good idea to run on trails, while of course staying under the MAF heart rate.

  • Andy says:

    Referring to your example further above:
    Shouldn’t it be possible to run a marathon much quicker than 7:45 pace if you can run a 10k with 6:30 pace?

    Best Regards

    • Andy:

      Yes, but you’d be talking about the very highest examples of aerobic performance. The chart isn’t meant to be representative of the creme de la creme of the elite—those who (1) have a physiology that is genetically heavily tilted towards distance running, (2) have cultivated that physiology for decades, and (3) also represent the high water mark of a population that already boasts attributes (1) and (2).

      As you close on the average physiological and genetic attributes of anyone but the .01% of elite marathon runners, it starts to look a lot more like that: we’re factoring in the entire population, from those who are better sprinters (but run distance) to those who are better distance runners.

  • Lila Burnett says:

    Is frequency of workouts more important than duration in terms of making progress?

    • Lila:

      Yes, within reason. For example, studies have shown that training twice a day every other day is more effective than training every day, for developing muscle. And in terms of distance running, it’s also important to train more frequently rather than with more duration since frequency has the advantage of (1) adapting you very well, and (2) reducing the total wear and tear on your body caused by each bout of exercise, which means that it’s easier to recover. And because recovery is quicker, so is adaptation.

  • Jerry Naughton says:


    One observation, two questions:

    I’m really enjoying this site and approach to training after hearing about it in “Natural Born Heros.” I got “The Endurance Handbook” shortly thereafter, and have started the approach over the last month. I also just got Mark Sisson’s new book “Primal Endurance” in which the MAF method is very prominent.

    The observation is that Sisson’s book put much more emphasis on nose breathing than I’d picked up here or in PM’s book. Maybe I just needed to hear it two or three times, but that’s the impression I got. Once the impression was made and I made a conscious effort, I was stunned at the difference — my heart rate climbs 4-5 BPM if I start mouth breathing compared to nose only, and then drift back down when nose breathing is resumed.

    The question is, I’m not on any medications, no injuries, been running (jogging, really) a couple of times a week for the last several months, so I was using 180 – 58 y/o = 122 for my target max rate. It struck me that although I don’t think of myself as sick or injured, I do use a CPAP for sleep apnea. I use it consistently and get good all night sleep. So, how would you score that on the 180 Formula?

    Question two — is there an ETA for the MAF app?

    Thanks for what you’re all doing!

    Jerry N
    Springfield, IL

    • Jerry:

      Perhaps we should emphasize nasal breathing more. I’m a huge fan of it myself. The reason that happens is because nitric oxide NO is created in the nasal pathway, which helps dilate the blood vessels and capillaries, letting blood flow more easily to and from the organs and muscles.

      Dr. Maffetone answered the question about CPAP below.

      The MAF app will be released January 2016.

      • SimonM says:

        Thanks for the timely (for me) remonder of the basics. I had already started an “aerobic reset” as I was feeling things weren’t going right and just revised my MAF HR down.

        What I’m noticing is that I can predict when my HR alarm is going to go off, as a few seconds before I will have switched from nose breathing to mouth breathing. But that’s not because of lack of NO,, but simply because my pace went up without me noticing.

        So on those days when my HR monitor is having a bad day (it is temperamental), I can switch it off and still know where I am.

        Now I’m wondering whether, as my aerobicness improves, this self-alarm system will kick in a beat or two later, or whether it will become an UNreliable indicator as I adapt to breathing more through my nose.

        • Simon:

          It definitely will. For example, I notice it because my breathing changes.

          • SimonM says:

            One other thought. NO production in the nose is fascinating, but I don’t think nose/mouth breathing is either/or. The nose only seals off if you’re underwater. That’s why if you do any kind of ex.phys. test where they are capturing exhaled gases, they will always give you a nose clip (if they don’t have a full-face mask). So when you have to start blowing off more C02 through the mouth as your pace goes up, that doesn’t mean you stop breathing through the nose.

          • Simon:

            As you mention, nose/mouth breathing is not either/or. However, you can drastically magnify the amount of air you pull in through your nose when you close your mouth—I think this is what Jerry was getting at.

            Insofar as you breathe from your nose you will be producing NO. The more gases you inhale through the nose, the greater your production of NO will be. Even when the nose isn’t (completely) sealed off, most people use the nose for moving only a tiny amount of their total gaseous exchange volume.

            Because of this, “nose-breathing” is a great vasodilation strategy.

    • Phil Maffetone says:

      Jerry, have to chime in here. If you’re using a CPAP I would count that as an injury as sleep apnea is an abnormality (one that can usually be corrected), so -5 on the 180-Formula.

  • Mick Wall says:

    After studying MAF for quite some time, i’ve never really seen any advice on the amount of weekly training hours required to make aerobic gains using MAF.

    Ivan, to quote yourself above “For example, I acknowledge this in my weekly training by going from 15-18 hours in the spring and fall to 20-22 hours in the summer to 10-12 hours in the winter.”

    Winter: 10-12 hours (1.7 hours a day)
    Spring/Fall: 15-18 hours (2.5 hours a day)
    Summer: 20-22 hours (over 3 hours a day?)

    Are you a professional athlete? 3 hours a day?!?!

    I’m not a pro, I have a job, kids and family to support. My wife would divorce me if I was running for 2 hours day every day. I only manage to run approx 20 to 25 miles a week, running 3 times a week, totalling somewhere between 3 and 4 hours per week.

    What is the expectation in my MAF times on those sorts of mileage and weekly exercise totals?

    I’ve embarked on a winter route for the next 3 months where I will only run sub 136 (44 years of age in January). Am I wasting my time? Will I see any gains?

    How many miles a week did the guy in the chart run on his 19-month training period using the same relatively flat 5k course?

    This key piece of info is the one that appears to be always missed in these charts and test cases, its the same in the big book of endurance. At no point do miles per week or exercise time per week mentioned.


    Sheffield, UK.

    • Mick:

      No, this isn’t advice. It’s just an example of my personal training routine, to make a point that isn’t about training volume, but about long-term oscillations in training.

      Furthermore (and because of the above point) it reflects total training time, not total running time. Some of that is strength training, and most of that strength training is under MAF.

      Given the person, you can make gains doing 1 minute a day—in fact, one of the ways in which I helped people get off the couch is getting them running 2 minutes a day, 5 days a week, for 2 weeks. Then we would increase the time by 2 minutes every 2 weeks.

      There’s no magical time at which you start having improvements. Form follows function. If you change your usual function to incorporate 2 minutes of exercise a day, form—the shape of the body—will follow it (granted, the changes will be minute, but they’ll happen nevertheless).

      The expectations are whatever will work for you, given your training history. For example, as a very young child I was a gymnast and runner, so I have a very, very long history of training. And yes, I’m a fast marathoner who is developing an ultramarathon body. The particular reason I’m upping my training volume like that is to distribute it in chunks throughout the day, to teach my metabolism how to switch gears from rest to training and back very quickly, to develop the metabolic flexibility needed for 100-milers.

      That guy was an elite triathlete—I think he was doing probably 10, 12 mile days. But if you’re doing exclusive MAF training, very few people would be doing more than 15 miles a day.

      Miles per week or exercise time per week cannot be mentioned because we all part from different points. Meb Keflezighi runs 10 easy miles on his off days. A training volume that would break your body would be too easy for him. There is simply no way to responsibly prescribe a flat training volume for everyone: the elite gymnast who wants to become a runner needs a different training volume than the elite runner who wants to become an endurance swimmer.

      If you run your usual volume at a lower heart rate, it’s a great starting point to develop your ability to burn fats. You know you’ve succeeded in training the fat-burning engine if you arrive home after your runs relaxed, and with an abundance of what I like to call “mellow energy.” It’ll be immediately obvious once you feel it—it’s peculiarly stable. The best way to improve isn’t merely to run slow and pray you’re not wasting your time. Keep track of your times: do an initial MAF test, and do another every month. If, after the first month, you are improving and you feel like you can up your mileage a little bit, do so.

      Being conservative pays.

      What I can tell you is that you can develop with surprisingly little time at the wheel. In fact, good enough rest and as little stress as possible (getting better sleep, reducing work stress, cultivating a particular home environment, eating well) are major, major contributors to making aerobic gains.

    • tw says:

      Andy Magness did a podcast on Marks Daily Apple over the weekend with Elle Russ discussing his training evolution from more to much less and the counterintuitive results. He is a multi day competition enthusiast. Worth a listen. No idea if Ivan listened to it as well but his post seems to reflect some of what I heard.

      • tw:

        I haven’t heard it, but I agree with the sentiment.

        Less is more—and particularly, less of a targeted and specific training plan is much, much more.

        For example, the bulk of my training time is spent doing very specific mobility, stability, and skill work at a very low intensity (the vast majority lower than MAF) and at the height of my running training I’m running perhaps 9 hours a week at MAF and 1 hour a week at a higher intensity.

        For me, training isn’t taking the car out to do laps, so to speak, but bringing it into the garage to run a thousand tests on it and figure out exactly which parts need to be updated and replaced. For this reason, a lot of my training looks like stability and mobility exercises that are more at home at the PT office than the gym. And it’s made me a very resilient runner—even though I’m constantly moving stuff around, it’s been a long time since I got a hotspot or shin pain (or pain of any kind, in fact).

        • Cristian Andrei says:

          Hi Ivan,

          Can you detail the mobility, stability and skill work please?


          • Cristian:

            It’s different for everyone. I use a full-body flexibility routine I learned from Dr. Nicholas Romanov at the Pose Method, and my stability work includes low weight single-leg deadlifts, Romanian deadlifts, half-kneeling chops, standing chops, “running ankle pulls” of my own design, wall sit-ups, etc.

    • James says:

      Hi Ivan,
      I did a mountain race in September (at a considerably higher altitude than I train at), all my long runs were at or below MAF as were most of the shorter ones. Intervals wise I tended to do intervals in the 5-8 min range with HR 15-20 bpm above MAF, although I didn’t do this for that long. I did one really hard 1 hour run (tried to simulate the end of the race as much as possible) 4 weeks before, more for psychological benefits. I didn’t wear my HRM for the race as I thought it wouldn’t be that useful with the altitude being very different to my training environment and also the nerves/stress/excitement of the race. Felt like I could have gone a bit harder at the beginning of the race but was generally pleased overall with the race, considering the environment I train/live in is very different to the terrain/altitude the race was in. Do you think my approach was generally ok?

      • James:

        Yes, I absolutely agree.

        An elite ultrarunner and good friend recently told me some of the most profound and useful ultra advice I’ve ever heard: he said, “you should be spending the majority of your ultramarathon getting to your race.” In other words, maybe your “starting line” is 18 miles from your finish line, maybe it’s 12 miles, and your ultramarathon is really all about getting to that distance safely and in one piece.

        I think this advice can really generalize to just about any other distance, and is particularly applicable to situations where the race environment is very different from the training environment.

  • Steve Meagher says:

    What should my racing heart rate be? Should I race at my aerobic threshold or faster? Should I also train at the faster heart rate?

    • Steve:

      It’s dependent on the mileage that you’re running. For example, if you want to run a 10-K, you want to be using glycogen at a rate that depletes your muscles fully by the finish line but not before. So, a typical 10-K heart rate may be 15-25 BPM above MAF. It depends on the person, so it’s very important that you test it out beforehand.

      For a marathon, you’d typically be looking at 5-10 BPM above MAF, and for a half-marathon it would be 5-15 BPM above MAF.

      We typically recommend that 80% of total athletic activity be done at or under MAF. However, to train for races, I like to recommend that people be competent running 15 BPM above and below their target heart rate: psychologically and physiologically, it’s much easier to tolerate the event. So, for a 10-K I’d recommend half-mile repeats at 15 BPM above the 10-K target heart rate perhaps once a week (depending on the person) as well as a 9 mile day just above MAF. I’d shake it up with different kinds of interval and plyometric training, but that would be specific to the person.

      The rest of the time, they’d be going at or below MAF.

  • Christian D. says:


    Was just reading thru this and i didn’t see the chart for the runner that went anerobic for awhile. I’m curious to see that chart/results!


  • Hi Phil,

    Really interested in your comment as regards “More recently, we have learned that heart-rate variability can provide radar-like warning of potential overtraining or poor recovery.” I have been following your training guidance and diet recommendations since Aug-2013. Your work and guidance have really has been quite a revelation for me. I have certainly seen an improvement (although not always continuous) in my performance. However my HR does noticeably oscillate up and down when running at constant speed in the range of ~5BPM around my target HR. Is this normal range, or does this imply I need to reduce my target HR, or am generally over-training?

    BTW – I am now 54 and still use a max target HR of 127 BPM.


    • Phillip:

      As long as you’re improving on a month-to-month basis, you’re doing OK. Generally speaking, it’s best to stay below 127. For example, I’d aim for 122, in order to create a 5 BPM buffer zone. That said, you’re almost certainly not overtraining. At worst, you may be slightly diminishing the speed at which you make aerobic gains.

    • Jerry Naughton says:

      My understanding is that the Heart Rate Variability topic refers to beat-to-beat variation. It’s an indication of the health and balance between the sympathetic and parasympathetic systems; and HIGHER variability is good:

      You need a heart rate monitor that collects this data (i.e., Polar H7 — my Scosche Rythm+ doesn’t fill the bill).



  • Janez says:

    For a mountain biker, would improvement in MAF test for running during the winter translate to better performance on the bike?

    • Janez:

      Yes. For several reasons, skill transfer from running to biking happens a lot quicker than the other way around. But since you are using different muscles while running than while biking, that transference won’t happen as fast as if you biked through the winter.

  • MP says:

    “The chart below reflects MAF Test results of a runner during a 19-month training period using the same relatively flat 5k course”

    Where’s the chart?

  • Tristram says:

    Is there a seasonality to HRV? I notice that a switch from mtb season to weight and concept 2 rowing ergometer for ski season has resulted in a drop off of HRV scores as we head into the winter months. Yes it may be overtraining but I’m not sure this is the case.

    Is there an optimal way to use the Concept 2 rowing machine in a MAF test as described above?

    Thanks for the plethora of terrific info on this site btw.

    • Tristam:

      Generally speaking, it’s not HRV that is seasonal, although it does reflect the body’s long-term cycles. The body is essentially winding down for the year and preserving it’s energy, in order to rebuild and prepare for next year.

      For example, I acknowledge this in my weekly training by going from 15-18 hours in the spring and fall to 20-22 hours in the summer to 10-12 hours in the winter.

      And you can use the rowing machine in a MAF test: just track power instead of speed relative to your heart rate.

Leave a Reply