Exercise and Medication: Why It’s Important to Adjust Your Training Heart Rate

By April 30, 2015 June 13th, 2017 Exercise

Many people are familiar with the 180-Formula as a way to increase fat burning, improve health, and get faster by training slower. For some individuals, reducing the training heart rate is a hard pill to swallow. By lowering the maximum aerobic heart rate by 10 beats, as indicated in the 180-Formula, the workout slows even more, further frustrating some people. The common complaint is: “I can’t believe how slow I am going!” But give yourself time. Be patient.

Many people of all abilities, including athletes, coaches, and healthcare professionals, have frequently asked me for further clarification of the 180-Formula. But the math is actually quite straightforward, with the Formula containing this caveat: If you are taking any regular medication, subtract 10. Not only is this relevant to prescription and over-the-counter drugs that modify your heart rate during exercise, it applies to any medication. The result is a further lowering of the aerobic training heart rate, slowing the intensity of the workout.

There are good reasons for this recommendation. First, some medications slow the heartbeat. This results in false information about how hard the body is working. In other words, you may workout harder but still have a low heart rate—artificially reduced by medication.

A common example is a group of drugs called beta-blockers, prescribed for patients with heart problems and high blood pressure. This drug reduces both the resting and exercise heart rate, although not always by the same amount. In some cases, a person can workout much harder without the heart rate elevating even into the aerobic zone. In this case, exercising at 125 beats per minute, for example, may be the same as 155 without the medication—so if your max aerobic heart rate is 140, you can easily be overtraining at 125. In fact, some people are unable to attain their max aerobic heart rate while on a beta-blocker.

In this situation, where medication significantly reduces the heart rate, the best suggestion is to work with a cardiologist or other healthcare professional familiar with exercise physiology who can help further individualize a drug’s optimal dose, and your exercise program.

Anti-arrhythmic drugs, calcium channel blockers, and other medications can sometimes reduce exercise heart rate as well. If you’re taking any prescription or over-the-counter drug, you should know whether it affects the heart rate.

Some drugs raise the heart rate. These include thyroid medication, Ritalin and other amphetamines, and even caffeine, which is found in certain cold remedies, pain relievers, and, of course, coffee, tea, and some colas. These drugs will often cause higher exercise heart rates, forcing you to slow down to maintain your maximum aerobic heart rate. This means that by following your heart rate you may have to reduce your exercise intensity. But don’t increase your max aerobic heart rate because of this—there’s another very important factor to consider.

A second reason to subtract 10 beats in the 180-Formula for a person on any regular medication has to do with overall health. The fact that a healthcare professional has prescribed a drug or recommended an over-the-counter one means there’s a health problem. In addition, there are the drug’s potential side effects.

While people often think many prescription and over-the-counter drugs are perfectly safe, or that the health problems associated with their needs are quite innocuous this is absolutely not the case most of the time. So being more conservative during exercise is important to prevent problems of excessive stress or overtraining from your workouts. There’s still a wide range of intensity below the maximum aerobic heart rate that will provide significant benefits. In addition, this will help with optimal development of the aerobic system often to the point where your doctor may reduce a drug’s dosage, or decide the medication is no longer necessary.

For competitive athletes, progress may be a bit slower, but they’ll still get faster at the same heart rate and improve their performances.

Even though many medications don’t directly affect the heart rate, the impact on health can adversely affect muscles, metabolism, and other systems of the body that promote health and fitness. An example includes some of the cholesterol-lowering drugs called statins, including Mevacor, Lipator and Altocor. These can affect muscle function, sometimes leading to exercise-related injuries. By making the 10-beat adjustment in heart rate, the risk of muscle problems and potential injuries may be reduced.

Another example is aspirin and other NSAIDs, which can interfere with proper recovery after exercise. By working out at a lower heart rate, the stress on the physical body will be reduced along with better recovery.

Even for a woman who is taking birth control pills or hormone replacement therapy, these medications have potential side effects that can adversely affect exercise activity. In this case, the levels of some B vitamins can be lowered, affecting liver function, energy systems, lactate production, and other important body functions necessary for optimal health and fitness.

For those performing higher intensity workouts, the potential problems of medications, and the reasons for prescribing them, can be amplified with an increased risk of complications. Consider that increased physical exertion itself is a risk factor that can trigger a heart attack. While lower heart rate workouts generally don’t do this, and in fact, protect you from a heart attack or stroke, anaerobic exercise with its associated higher heart rates can increase the short-term risk of death from a heart attack. So does the high intensity associated with athletic competition—it doesn’t have to be a 26.2-mile marathon, 5K run, or two-hour bike ride.

A note on caffeine:

I don’t recommend making further adjustments in the 180-Formula for those drinking a large cup (or two) of coffee before working out. Clearly, this can affect the heart rate. But like eating a bowl of junk-food cereal or a bagel, which can adversely affect endurance performance by reducing fat burning, I choose not to adjust the training heart rate for these habits.


  • Angelos says:

    Hi Ivan,

    I consulted my cardiologist and he informed that Irbesartan does not have any effect on heart rate and since I don’t take any other medication , nor do I have any other side effects then I do not see any reason of substracting it.

  • Angelos says:

    Hi ivan,
    A few months ago ,I was diagnosed with high blood pressure and the cardiologist instructed me to take a low dose of irberastan (38 mg per day)

    Irbesartan is an angiotensin II receptor blocker (ARB). It works by blocking a substance in the body that causes blood vessels to tighten. As a result, irbesartan relaxes the blood vessels. This lowers blood pressure and increases the supply of blood and oxygen to the heart. It has nothing to do with beta-blockers

    Now my blood pressure is perfect (12/8) and I don’t have any side effects.

    Speaking about the definition of MAX aerobic hear rate, do you suggest to substract 10 from 180-Age formula?

  • David Warmerdam says:

    Hi Ivan,

    In 2011 I completed a 70.3 and in 2012 I trained for and completed a full Ironman. For the full IM I trained at 180-age as per an online Mark Allen article, with some success, improving my running pace by about 50 sec/km and my cycling pace by 5km/h over 3 months.
    My HRM doesn’t work in water but I’m 100% sure that almost all my swimming was above MAF heart rate. Also, I have been taking an ACE inhibitor (Prexum) for the past 15 years for hypertension. I discovered after buying the “Big Book” that I should have also deducted 10 beats from my MAF heart rate.

    The above leads to 4 questions:
    1) I am starting to train for another Ironman. Given my past “success” without deducting the extra 10 BPM for regular medication, should I do so now?
    2) Why does Mark Allen, now also a successful coach, not recommend the 10 beat deduction for regular medication?
    3) Is MAF training and progress sport specific, given that I made significant progress with cycling and running while swimming at above MAF heart rates?
    4) Almost all the anecdotal evidence I have read, including that in the “Big Book” is of already trained athletes who then make significant progress by switching to MAF. This was true in my case as well. This time around I am finding running progress very slow, but I have not run for the past 2 years (I’ve been paddling and swimming – not MAF :)) Is there something behind this observation?
    I’m now 55 years old, if it makes any difference.

    Thanks, David

  • Robin S. Hicks says:

    I am on multiple medications (Beta-blockers, Anti-depressants, Statins, and Mood-stabilizers). Should I stick with the 10bpm reduction, or go higher?

  • Jess says:

    Should I lower 10 beats for taking a prescription antidepressant? Thanks

  • jean-francois says:

    Hello Ivan,

    I’ve been running/swimming/climbing regularly for some years now. Not really compretition, just recreation cause I’m too slow.
    Further to atrial fibrillation during or just after sport (maybe I was traning too high too often),
    I decided to give a try MAF method that’s look quite interesting.

    I’m 51 and taking now on daily basis anti-arrthymogenic drug called flecainide, a class Ic antiarrhythmic agent that works by blocking the Nav1.5 sodium channel (wikipedia).
    I computed MAF HR then with 180 – 51 -10 = 119.

    As a result, after 5 weeks of training supposed to be run:
    – uphill: I can just walk, even stop walking sometimes to not go beyond 119
    – flat road: I can just “jogtrot” for 50 meters and needs at least 100 meters walking to slow down HR
    – downhill: not much better than flat roads

    So, altghough I enjoy it, and happy to never be tired, I’m a bit frustrated to not be a runner anymore.

    My question then is: do I need to susbtract these 10 points with my medication?
    I understood that some anti-arrthymogenic may not impact HR and then not need adjustement for MAF formula.

    Thank you in advance for your help,
    this method seems great, but I’d like to be sure I’m using it the right way and not loose months of bad training.

    One point about climbing: I realized that HR during this exercise is between 125 and 170! So no way for MAF for this sport, at least for the moment.


  • Kathleen says:

    Hi! I had my complete thyroid removed along with radical neck dissections (lymph nodes) due to thyroid cancer in mid 2013 (I also had been diagnosed with Graves Disease in 2011). Consequently, I have to take thyroid meds – levothyroxine and supplement the levothyroxine with liothyronine because I do not convert the T4 to T3 effectively. I have been a long time cyclist and trail runner – 25+ years. After the thyroid problems, I have struggled to coax the body to accept or adapt to any type of training load. I adapted the MAF HR training the beginning of June 2015 and still see very little overall improvement. We have determined the the thyroid meds keep the overall HR higher whether resting or running or riding. It has been very frustrating to try training when it seems like my body is conspiring against it, let alone consider racing ever again. Any words of wisdom in how to deal with the medication induced increased HR in trying to train or perhaps race again? Mostly, in the past, I have been an infrequent but successful age group trail half marathon/25k racer. It seems those days may be well past?
    I am 48 and eat a higher fat, lower carb, moderate protein diet. Thank you for any insight you might offer!

    • Kathleen:

      I’m sorry to say that the answer to your question is “probably.”

      Since thyroid hormones affect the basal metabolic rate, it’s possible that your metabolic rate fluctuates far more in relation to the hormone medication than it does to the onset and end of exercise. The bottom line is that this makes it very difficult to switch from “exercise” to “recovery” mode and back—in other words, whether you switch, or how fast you switch, is up to the medication. I’m sorry to say that I can’t give you any advice on the topic of Graves’ because this is a medical issue and I can’t comment on medical topics, both because (1) I’m not a doctor and (2) any advice that I might give may conflict with the advice of a doctor who knows your particular situation in depth.

      This means that it’s extremely important to be conservative with what you consider to be your MAF heart rate: a heart rate that’s too high can put a lot of stress on your body in these conditions.

      That said, there’s enough distance runners with Graves’ or Hypothyroidism that a lot of doctors who specialize in athletes may be able to help you, particularly in terms of calibrating your hormone medication to your training regimen and training needs.

  • Natasha says:

    I am 40, 120 pds, 5’6” and I take an anti-arrythmogenic drug, very low dose, which seems to effect my HR. According to your site, my max aerobic HR is 140, so I subtract 10 for the beta blockage med, puts me at around 130, which is right where my HR has been when I run – it usually runs around 128-140. Should I change my garmin HR max to reflect this? how does one adjust their HR monitor to reflect the Maffetone HR? Also, does a lower HR burn less calories? (the last question is just curiousity…) Thanks!

  • Natasha says:

    Hi, I am on a low dose of anti-arrthymogenic drug, and I am a runner (ok’d by doctor). I just do not run competitively any longer, but I can do endurance runs. My heart rate on my regular runs ranges from 125 (beginning a run) – 135 or even up to 140 towards the end of a run and if I am really pushing it. I cannot push the pace like I used to, but my aim now is to stay fit, build endurance and hope to get faster along the way. So I figured out my max hr using your method and that would put me at 140, so I then subtract 10 and that would put me right where I had been running. My question is this: is the calorie burn the same? and does hr effect calories burned? My Garmin is off so should I adjust the max hr on my Garmin too and put it at 130? Thanks for the help.

    • Natasha:

      Sure, adjust your Garmin if that helps. And HR does affect how many calories are burned. (A high heart rate will burn many more calories than a low heart rate). However, consider this: When you do HIIT to kick up your heart rate, your body primarily burns sugar, since it has to supply energy quickly to the muscles, and can’t get it from fat, even if your aerobic system is well-developed. When you train at your MAF heart rate, 100% of the calories you burn should come from fat (theoretically). Furthermore, there is very little wear and tear on the body at the MAF heart rate, meaning that your training volume can be far greater than if you trained at a higher heart rate.

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