Learn how to measure your heart rate during a workout, how to set heart rate zones, and how your heart rate should feel during exercise.
How to Track Your Heart Rate
When you track your heart rate, you can also measure
your resting heart rate, which will get lower as you get fitter and
your heart rate recovery after exercise, since a heart rate that has dropped by less than 12 beats per minute one minute after stopping a workout could indicate increased risk of heart attack.
Finally, don’t give much credence to the number of calories your heart rate monitor might tell you you’re burning--they can overestimate by up to 20%!
How to Find Your Target Heart Rate Zone
If you want to use your heart rate to help you exercise safely or properly, you’ll first need to figure out your heart rate zones. Though you might be tempted to use a heart rate zone chart like the ones that appear on gym walls and cardio equipment instructions (see what one looks like here), which lets you approximate a target heart rate zone for exercise based on your age, it’s important to realize these charts aren’t accurate.
Interestingly, the heart rates used to create these charts are derived from the equation of “220 minus age” to determine maximum heart rate. That formula was originally devised in 1970 by two physicians and was not based on research, but rather from simple observational data. It is widely considered among health and fitness professionals as a poor predictor of maximum heart rate, and two decades of research have shown it to be highly erroneous.
Though you could test your maximum heart rate yourself, that can be both uncomfortable and dangerous, since it requires you to exercise at 100% intensity to record the maximum heart rate you can achieve. A better way would be to simply do a submaximal test. This is an accurate way to determine your personal heart rate zones, and one version of a submaximal test is mentioned in my article “What Is the Fat Burning Zone”.
The Best Way to Find Your Target Heart Rate Zone
To do this test, simply warm up on a bike for 10 minutes. Next, pedal at your maximum sustainable pace for 20 minutes. You should be breathing hard and your legs should be burning, but you should be able to maintain the same intensity for the full 20 minutes. Record your average heart rate during those 20 minutes.
Now, let’s say you want three heart rate zones for your exercise sessions. Take that average heart rate and multiply by 80-90% for your easy, aerobic heart rate, multiply by 90-100% for your harder, calorie burning heart rate, and multiply by 100-110% for your high intensity interval heart rate. This is a simple method that works for most people, but for the endurance athletes I coach, we often use up to six heart rate zones!
A Heart Rate Mystery
As promised, I will finish with a heart rate mystery, recently presented by a woman who wrote in to firstname.lastname@example.org. Here is what she said:
“I am a fit 51-year-young woman. I have always had this weird thing with my heart rate. When I exercise at [my optimum target range, which is 155 bpm (80% of 193, my max)], I don't feel like I'm doing any work! I feel like I am just slacking off and not getting a good workout. Is this just a perception problem on my part?
If this woman’s max heart rate is 193, then she probably has a very low stroke volume, or amount of blood the heart pumps with each beat. That can simply be due to a genetically small heart. If her heart doesn’t pump much blood with each beat, it has to beat more times per minute, and if this is the case, even at low exercise intensities her heart rate will naturally be higher.
This woman also told me she has a resting heart rate of 56, which means she has a very large heart rate reserve (the difference between maximum heart rate and resting heart rate). That indicates she probably has a great deal of cardiovascular fitness, which means that even at higher rates, she’ll feel relatively comfortable.
So ultimately, she can’t accurately use a maximum heart rate equation. If she goes back and does the test I described earlier in this article, she’ll discover her “threshold heart rate,” the heart rate at which breathing becomes deep and the muscles begin to burn. She can then use 80-90% of this number for easy aerobic work at a conversational pace, 90-100% of this number for cardio fitness at which the legs are burning and she is deeply breathing, and 100-110% of this number for hard intervals at which she can exercise for just a few minutes. Since she appears to have a high degree of cardiovascular fitness, she may need to increase these numbers by a few percentage points to get even more benefit from her workouts.
And remember, if you’re ever unsure about heart rate beat skipping, chest pain, rapid heart rate, or any other heart rate conundrums during exercise, the best bet is to go talk to a doctor, who can perform medical tests to find out if there are any serious problems.