Follow Your Heart Rate?

By Brian MacKenzie with Anthony Roberts

In CrossFit Endurance, Rest Day/Theory

October 24, 2011

PDF Article

Brian MacKenzie and Anthony Roberts explain the origins of the maximum heart rate number and why it so often tells us so little.

Ever seen this formula?

220 - age = MHR

It’s the standard formula for determining maximum heart rate, or MHR. Subtracting your age from 220 represents the highest heart rate one can safely achieve through exercise stress. This formula tells us a 15-year-old has a maximum heart rate of 205 and a 25-year-old has a maximum heart rate of 195.

If I started training for 5K races at the age of 15 and continued for 10 years, my MHR would still be 195 when I reached 25 years old, according to this formula. After 10 years of endurance training, it would actually be lower than when I started training at 15. The formula tells me I’d have the same maximum heart rate as an untrained person of equal age after endurance training for an entire decade!

Ever wonder where MHR estimates or heart-rate training came from? Have you ever strapped on an HR monitor to see what your heart is doing? Or maybe you checked your resting pulse? It must be important, right? The mainstream medical industry, as well as the general fitness community, has set up parameters for what is healthy based on your resting HR, or RHR.

Fair? Not in the slightest.



24 Comments on “Follow Your Heart Rate?”


wrote …

Anecdotal evidence: I recently turned 50, and I recently had a stress test. According to "the formula" my maximum heart rate should be 170. The technician stopped the test when my heart rate was 183. Nothing "blew", except air out of my lungs.

And no, I am not "fit", nor an athlete. I am still at puppy level when I do CrossFit workouts.


wrote …

I understand the article that has it's problems with HRM, but never actually addresses a fix for it. Obviously a top performing athelete will have different values than a sedentary person, but I would say for the lay person it probably fills the need 99% of the time. After all, top performing athletes are probably the top 1% of physical specimen.

Anyway, as someone who is out of shape and working to get into some decent shape I use my heart rate monitor not to stay below a maximum heart rate, but to stay above a minimum heart rate to make sure I am pushing myself enough. (one of my weaknesses may be that I would rather be sitting on the couch playing PS3 that busting my arse for 20 mins doing a WOD, but I know the second is more important to my well being)

Anyway, always appreciate the CFJ stuff and always respect Brian M.


Ben O'Grady wrote …

It's common knowledge among endurance athletes that the "formula" is merely a rule-of-thumb or a starting point for determining HRM. You would want to test yourself to determine your true HRM...Brian described one such test in his article with the rower. I'm 36 and my max heart rate is 186-187. The formula tells me 184, so it's close enough for my purposes.

HR isn't the be all and end all, but rather another data point and a helpful one. Other options include measuring blood lactate and power output. It should be noted that measuring heart rate is the *cheapest* option if you're doing aerobic training. You can buy a decent HR monitor at Sports Authority for $50 and easily implement a fully fledged training plan using that one tool and some common sense. So why all the haterade?


wrote …

I agree with Brian K and Ben with the over-kill approach against the generic formula. However, as a health care provider that tailors toward a more athletic population, I do get frustrated with the re-education process around this issue. A few problems I encounter -
1) People using it as a crutch instead of a way to generally measure intensity... "Oh my God, I need to slow down because of my HR" instead of correlating perception, stress, and HR to making necessary bio-psycho adjustments during training.
2) People using the 220-age for percentages/zones without subtracting their resting HR... doing so will boost the training zones by 3-6 bpm; ((HRmax - RHR)x desired %)+ RHR; as well as, neglecting to find a more accurate HRmax through various tests.
All in all, using heart rate to help train more efficiently is much like Crossfit Endurance and Crossfit in general... it needs to be understood prior to application.


wrote …

Yeah. I've never taken the MHR charts printed on the tread mills to apply to me. I always assumed those were for the folks just getting started in the gym.

I'm 44 and February will be 5 years of Crossfit for me. For the first year I wore my HRM regularly with every work out mainly because my heart had never been stressed like that before and, because I was not working out in a box (a.k.a alone), I wanted to understand if I was doing something harmful to myself.

As I got in better shape I began using the HRM less and less. But, it does provide interesting information. If the body is working correctly HR is largely a function of how much O2 your body requires. If I do Fran one week at 5:12 and the next week at 5:55 and view the HRM real time playback I can usually find that my average HR was measurably higher on the day that I had a longer Fran time. Diet? Sleep? Stress? Combination? Who knows for sure? What is known for sure is that if your body is not getting the O2 it needs to perform there is a reason and your HR can be a data point that gives you insight as to what that reason may be. Whereas if my average HR is lower but my Fran time is longer then perhaps I know I have a focus/mental issue.


wrote …

BTW. I've always wondered what a guy like Spealer or someone like Annie has as an average HR for a Fran or other named WOD. I'd just be curious how much O2 they need to perform at their elite level.


wrote …

I am a woman at the "other" end of 60 and have been working out seriously for about 5 years using a HR monitor. I am now familiar with its' workings and aim to achieve a %average heart rate, i.e. 123 for a session, but when I am on the bike or doing kettlebells I like to push harder to bring my heart rate up into the 130+ range, and working until I feel like vomiting. That's my criteria.
It's really just a motivator to work harder, which for me is a good reason to wear one.


wrote …

"Intuitively, we know a NASCAR driver or F1 racer would be shredded by a boxer, marathoner and a soccer or rugby player in terms of endurance, even though the literature tells us they have similar heart rates during competition."

I'm not a huge racing fan, but I do know that the training regimens of most (if not all) pro drivers these days includes a ton of intense physical training outside of driving a car. I'd be willing to bet that many of them are in better shape than most amateur marathoners. In my couple minutes of Google searching I found this article about IndyCar drivers who run 13.1 in 1:45 -- not bad.

"In other words, physical stress doesn’t necessarily play a role in HR because sitting in a car driving around a track does not require much physical activity."

Again, I'm not a huge racing fan, but I understand that driving a car at those speeds for that period of time actually does take a highly physically trained person to be successful.

Footnote: I'm not a fan of HR as a training measure either, other than to use at first to get a feel for how one's body reacts to various intensity levels. I stopped using a HR monitor 5 years ago. I love the anecdote in the article about the guy who refuses to go above 166. I've heard this so many times and I thin it's counter-productive. Props to the commenter above who said they use HR as a way to push harder instead of a finite limit of exertion.


wrote …

I agree with the point. HR is not the be all end all of measuring intensity, but if it is done correctly, it can be helpful. I think Joe Friel's Triathlon Training bible does a really good job of teaching you to test your MHR (for all three sports because they are always different) and then using it to regulate your intensity.

In normal crossfit we don't regulate intensity. We say just go as fast as you can. And, mathematically, we know power output goes up as long as time goes down for the same WOD. We can actually mathematically and scientificially record fitness increases. However, it's probably not a good idea to tell someone training for a marathon to just run as hard as they can everyday. Even crossfit endurance says to run at 95% for your tempo run, or "hold" intervals at a given pace.

Most of us can just use Rate of Perceived Exertion (RPE) to self regulate the appropriate effort level. This is actually one of the best ways to gauge intensity. However, if you correctly test your MHR for the given sport (and repeat the test as fitness improves) you can get even closer to running at 95% of your max on a tempo run.

Now, for biking, we can actually buy a powermeter and measure our second by second power output. Which, I assume the crossfit endurance community would embrace, because power, according to crossfit's theories, is synonymous with fitness (accross broad time and modal domains). So, if you are biking just throw out your heart rate monitor and get a powermeter (assuming you can afford it) and you can measure your fitness precisely. However, measuring running power, is very difficult if you are not running on a treadmill. You can, in this case, use a heart rate monitor to approximate your running power output. To me, this would be the one legitimate reason, to use a heart rate monitor to measure intensity and gauge fitness improvements.


wrote …

Great article guys! Give me a stopwatch over a HR monitor any day!


wrote …

read this during my ex phys class.
finally learned something useful in said class haha


wrote …

Color me ignorant but I have never tested my max heart rate. I never saw the point. Won't my body tell me to stop when its time to stop? If I listen to my body won't I know what a sustainable pace is for my fitness level?


wrote …

Any thoughts on using a heart rate monitor in the morning when first waking up to determine if an athlete is over training. I have been told that if your heart rate is unusually high in the morning that it is a sympton of over training. Any truth to this?


wrote …

Ah yes another opportunity to take a dig at the academic community.....

Any exercise physiologist with half a brain could tell you that yes absolutely the 220 - age formula is seriously flawed. As you guys point out the history of this formula is quite dodgy. It doesn't take a rocket scientist to figure out that ANY predictor equation, no matter how impressive or how many variables it uses (and there are many equations for predicting max HR in different populations) will be subject to potentially large error when applied towards individual humans who respond and adapt to exercise in highly variable fashions.

Want to know your maximum heart rate? Measure it directly. Do a 3-5 minute workout or hill repeat as fast as you possibly can (eg. Fran) and that'll likely do it. But it won't tell you much of anything useful. Better yet, if you are an endurance athlete, forget about maximum heart rate and find out about threshold heart rate. More sport performance relevant.

It remains in the literature because (a) it is easy to remember and (b) it is "reasonably" accurate "most" of the time (standard error of estimate) and potentially perfectly adequate for Average Joes when used in combo with other things (eg. RPE).

Heart rate is a non-perfect intensity measure, for many reasons, the least of which is the 220-age thing. It is useful for endurance athletes and almost useless for CrossFitters.


replied to comment from Hector Reyes

Yes Hector high waking resting heart rate can indicate OTing, but not very sensitively. HR responses to orthostatic tests (lying to standing) can be useful too.

But never rely on heart rate responses alone to diagnose anything: too many variables affect it.


wrote …

Finally, I always believed in this ideal. I couldn't stand sitting in on certs that pushed the 220-age=MHR formula. K.I.S.S.Principle is the best to follow. Base your WOD's on how you physically feel. Not some $300+ dollar HRM.


wrote …

Thank God for Tony Webster; he makes more sense in his brief reply than the rest of the entire article! As stated, 220-age is flawed and known to be; it doesn't take a 6 page article to prove this. Equally, as stated in the article, 220-age gives an approximation for the previously sedentary/deconditioned, is quick and easy to calculate in your head, and as such provides a useful starting point for that population.

Whilst it's true that many cheaper HRM's base their zone calculations on this simplified model, most more advanced units allow use of alternative estimates of MHR, Karvonen formula to establish zones that take account of resting HR, or manual entry of custom zones based on alternative testing. This last option is most likely used by the committed endurance community; as Jim McKnight points out, many will be using Joe Friel's well known tests to establish their own HR zones which can be of significant value for running, and for cycling for those who cannot afford a power meter. As Friel points out, there is little value in any case in knowing MHR; his HR testing focusses on the far more useful values of aerobic and anaerobic thresholds and he is at pains to point out that these are changing figures that require periodic re-testing.

The authors further suggest that HR monitoring is of little or no use to 'bona-fide endurance athletes', but contrary to this, as experience is gained using an HRM athletes will come to a much clearer relation between HR and RPE, and so the level of exertion they are able to sustain for a given duration or distance. This has a significant value on those days when the athlete may just be feeling under-par, less motivated etc, giving them a measured value of level of exertion rather than a perceived value. Cross Fitters need hardly been told that we are almost always capable of more than we think, and that measured HR that is lower than the perceived efffort can be just what is needed to spur an extra effort and lead to maximum performance.

HR monitoring is also, as other posters have noted, and as the authors allude to but then bizzarely (conveniently) ignore, a useful indicator of total physiological, psychological and immune stresses on the body. Of course it is not easy to differentiate which of these is responsible for a given HR but as above, an experienced athlete will learn to associate particular feelings of well-being or otherwise with an normal or elevated HR (resting, orthostatic or elevated by exercise stress).

The authors suggest that endurance training should result in a change in MHR (they don't say in which direction, though the article reads as if expecting MHR to increase or at least drop off less with age). I'm not aware of research to suggest this (though happy to be proven wrong), but rather that resting HR can be expected to lower through increased cardiac output as stroke volume increases, hence the value of the Karvonen formula or individual testing in determining training zones. Also expected, as Friel notes, is a decrease in decoupling; that in the trained athlete HR will rise by only a small percentage in relation to power over an extended period. This is an excellent indicator of aerobic fitness, and the HRM in conjunction with a steady state workout provides a quick and easy way to test this.

Suffice to say that in summary I consider there are as many holes and half truths in this article as there are in the 220-age formula itself. To simply dismiss the formula and HR monitoring as a whole is over-simplistic and a disservice to readers. Like many other equations and tools, 220-age and HR monitoring are useful if used correctly for applicable populations and irrelevant and misleading if used incorrectly on inapprporiate populations; that is a reflection on their application, not the equation or tool.

I should finish by pointing out that I am far from being an 'unbeliever' or 'hater' of CrossFit Endurance. I am a CF L1 coach, long-time triathlete and my own training had been heading further in the direction of CFE well before I was aware of CF or CFE.

For those interested, Joe Friel's blog can be found at Whilst his approach differs in many ways from the CFE approach, he too firmly believes in the neccessity of intensity over volume in advanced training. To quote from a July blog post:

'One of the best reviews of the scientific literature on the topic came from Laursen and Jenkins at the University of Queensland in Australia (Laursen, P.B. & D.G. Jenkins. 2002. The scientific basis for high-intensity programmes and maximizing performance in highly trained endurance athletes. Sports Med 32(1):53-73). To quote from the study:

"Increased volume for highly trained athletes does not appear to further enhance endurance performance or associated physiological variables. For athletes who are already trained, improvements in endurance can be achieved only through high-intensity interval training."

This is a point I make repeatedly in this blog: the key to success for advanced athletes is intensity—not volume.'


wrote …

I enjoyed this article up until you mentioned that drivers are not endurance athletes without providing evidence. "Intuitively, we know a NASCAR driver or F1 racer would be shredded by a boxer, marathoner and a soccer or rugby player in terms of endurance, even though the literature tells us they have similar heart rates during competition."

What is intuitive about that? Please don't resort to the same assumptions about fitness you complain about. I find your statement about as intuitive as the 220 minus age idea.

A simple web search showed that the current F1 champion, Sebastian Vettel spends up to five hours a day on endurance training.

The previous F1 champion, Jenson Button, recently finished 3rd out of 500 in his class in the London triathlon.

Please don't include blind assumptions in articles that aim to get rid of them.



wrote …

What starts off as an article discussing a formula ends up an article on an attempt to discourage the use of heart rate across the board.

The heart rate monitor business is a multi million dollar industry so before we all recycle our heart rate monitors, maybe we ought to look at a different perspective.

The author takes a product that is specifically designed to enhance performance and makes it out to be something that inhibits us. Heart rate monitors are used by the NFL, the NBA, the MLS, the World Cup Teams, America's Cup, Nascar, MMA, Boxing, the Olympics, etc. Some of these teams are making million dollar plus decisions based off of heart rate. Are these Performance Directors all out of their minds? Can we really tout that their are no benefits to using heart rate? Maybe the wrong questions are being asked by the author.

To start off, there is not one athlete that I know who ever assumes that 220-age is the right formula for them. The author is correct in saying that the formula was never meant for this. Any serious triathlete also knows their Max HR very rarely comes into play when training and AT is the focus point. Any serious triathlete also knows that their AT will be different for all 3 disciplines of swimming, biking, running.

And not to repeat what others have responded previously. (Brendan Moore) Crossfitters can 100% increase their performance by utilizing a HRM even if its just off of basic RPE alone. Understanding intensity and understanding recovery and hence therefore understanding and listening to what your body tells you should not be looked at as a "governor" but more as a way of knowing your limits and what your body is capable off.

We have those key workouts in Crossfit that prove our fitness (ie:FRAN). So if you want to prove that you have given it your best effort than why not have it validated on your wrist?

A full hard effort should not only be written on the white board with your name and your time but by also how hard you pushed your body and pumped your most important muscle.... your heart.

Being someone that does Crossfit but is also a Professional Triathlete I would not have had half the success in both sports if it wasn't for truley listening to my own body. As a chronic overtrainer in the past, I now know when to rest and have seen massive improvements in my competition for both sports. And I attribute that all to my heart rate monitor.


wrote …

good article but as others have said the info about racing drivers isn't backed up by any data.

that shows some of the stressed involved and also provides hints as to the training required.

Please back things up with data!


wrote …

Before her two workouts on separate days, Elizabeth's heart rate was between 80 and 85 beats per minute.

After 14 minutes and 46 seconds of doing CrossFit, Elizabeth's heart rate was 220 beats per minute. After 14 minutes and 46 seconds on the treadmill running at six miles per hour, her heart rate was 190 beats per minute. In this case CrossFit has the edge.

Read more:


wrote …

This is a great article and brings home the point that taking a reductionist approach to training can often lead to poor results.

I strongly believe in knowing my heart rate zones and "RQ" (respiratory quotient)and using a heart rate monitor during competition when I know I will be exceeding my stored energy reserves... such as a half or full IM, 100km bike race, etc. I perform a VO2/VCO2 test on my clients so they know their heart rate zones for pacing and fueling requirements. Check out this link on Joe Friel's Blog (it is great for taking the guess work out of fueling and pacing)...

But when your doing CF and CFE training put the heart rate monitor away (unless it is a tempo day) and just crush your workouts.



wrote …

This article is ok, but really only touches the surface. What replaces MHR as a guide to intensity? In competitive cycling max watts per given heart rate are tracked with great results. The point with heart rate monitoring is to use it to learn about one's response to training. That old 220 minus your age has been known to be crap for many years, at least since the 80s for anyone of any sophistication. Heart rate repsonse to training is data. The point is to learn to use it in creative ways. One simple one: it is an excellent way to tell if you are dihydrated as increased heart rate is often a sign of dihydration. Like any fact heart rate needs to be interpreted to be useful.


wrote …

At a whopping 39 years old I recently had a stress test done. Now I should have stated that I have been doing crossfit since Sept 0f 2011 and proir to that I was just lifting weights with minimal cardio work. When I say crossfitting since Sept I should also say I dove in head firts and go 5 times a week and sometimes twice a day. All that said I know my cardio has a long way to go. The stress test however was funny to me. I forgot that I had the appointment and after finishing the morning WOD I stayed to do some additional squats. My legs gave out before my lungs did on the stress test. When I went back to see the Doc for the results he said my cardio level was borderline of what they consider and elite athlete. I laughed, pointed at the crossfit shirt I was wearing and said, "like the shirt says, forging elite fitness."

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