December 09, 2016
Your Heart Beat and Your Health

Your Heart Beat and Your Health

by Berkeley Wellness  |  

Your heart rate during exercise, as well as at rest, can tell you a lot about how fit you are—and perhaps even some other things about your health. Here’s the lowdown on your heart rate.

What should your heart rate be at rest?

Resting heart rate, or pulse, refers to the number of times your heart beats per minute when you are at rest. Though a normal range is 50 to 100, most people’s hearts beat 60 to 80 times a minute. Above 100 is considered a rapid pulse, called tachycardia; an unusually slow resting heart rate is called bradycardia.

Resting heart rate varies from person to person and over the course of the day, due to genetics and other factors. Your heart rate is faster when you get excited, anxious, or angry or if you are in pain or have a fever. And it rises temporarily if you smoke or drink a lot of alcohol or coffee.

On the other hand, your resting heart rate slows during sleep and tends to be lower if you are very fit. Certain medical conditions, such as thyroid disease, and some medications may affect resting heart rate.

What should your heart rate be during exercise?

To benefit most from aerobic exercise, you should work out hard enough to raise your heart rate to its training zone (target heart rate) for at least 20 minutes on most days. This enhances your aerobic capacity—that is, the ability of your cardiovascular system to deliver oxygen to the body’s cells during exercise.

The simplest way to compute your target heart rate is to subtract your age from 220—that’s your maximum heart rate—and then calculate 60 and 80 percent of that number. For example, if you are 50, your maximum heart rate is 220 minus 50, or 170. Then multiply 170 by 0.6 (for the low end) and by 0.8 (for the high end), which gives a range of 102 to 136. Your heart rate should fall between these two numbers while you exercise. If you’ve been sedentary, start with 50 to 60 percent of your maximum rate. Trained athletes, on the other hand, may aim as high as 90 percent.

How do you measure your exercise heart rate?

Hold a finger gently over the carotid artery in your neck or the radial artery on the underside of your wrist (on the thumb side); count the beats in 15 seconds and multiply that number by 4 to get the beats per minute. Don’t stop exercising while you do this, since your pulse will drop right away. Some gym machines calculate your target heart rate (after you enter your age) and measure your pulse, or you can use a heart rate monitor.

Once you learn how it feels to work out at your target heart rate, you should be able to estimate your heart rate just by focusing on how you feel—by paying attention to how hard you are breathing, how much you are sweating, and how hard your heart is pumping.

This “rate of perceived exertion” is a fairly accurate measure of how strenuously you are working out. Or you can use the “talk test”: if you can just engage in conversation, your exercise intensity is about right.

How long should it take to reach your target heart rate?

That largely depends on how conditioned you are. If you are in poor shape, your heart rate will go up quickly with exercise; if you are in good shape, it will take longer. If your heart rate is naturally low, you may have to overwork to get into the standard target zone; if your heart rate is high to start, you may get into the zone too easily.

A more complicated formula for determining target heart rate takes into account your resting heart rate and changes in your aerobic fitness level as you improve with training and usually yields a higher range. But for most people, the simple method is adequate. A more accurate target rate can also be determined by an exercise stress test, which your doctor may recommend if you are first starting an exercise program.

How quickly should your heart rate drop after exercise?

The length of time it takes for heart rate to return to normal is a good measure of fitness. The more fit you are, the faster the recovery.

Your heart rate drops most sharply in the first minute after you stop exercising; it should then fall about 20 beats a minute—a drop of less than 12 beats a minute is considered abnormal. This “recovery heart rate” is measured as part of an exercise stress test.

Does regular exercise lower resting heart rate?

It may reduce it somewhat over time. Aerobic activities (such as jogging and cycling) enlarge and strengthen the heart so it pumps more blood with each contraction. Not every exerciser experiences this reduction in heart rate, however, and it may take years of exercise for it to occur. But low resting heart rate is often associated with high cardiovascular fitness, and lowering the rate over the course of an aerobic fitness program is a sign that you are achieving a training effect.

Studies have shown that people who work out regularly have resting heart rates about 10 beats per minute slower, on average, than sedentary people, and well-trained athletes generally have heart rates 15 to 20 beats lower than average. Even if you don’t experience a drop in resting heart rate over time, exercise reduces other heart risk factors, such as high blood pressure, high cholesterol, and obesity.

High resting heart rate: a risk for heart disease?

In general, a slower resting heart rate is better than a faster one, because a faster rate puts more stress on your heart and blood vessels. In fact, studies have consistently linked faster resting heart rates with increased risk of heart disease and death from all causes, independent of fitness level and other cardiovascular risk factors such as high blood pressure, high cholesterol, and being overweight.

A higher heart rate has been linked to poorer outcomes in both healthy people and those with heart disease. Most studies have found a stronger association in men, but a 2009 paper in the British Medical Journal, of nearly 130,000 postmenopausal women, found that those with the highest resting heart rates were more likely to have a heart attack than those with the lowest rates—especially women ages 50 to 64—after controlling for other risk factors.

Resting heart rate may be an even better predictor of premature death than cholesterol and blood pressure, according to a recent review paper in Progress in Cardiovascular Diseases—though there is no consensus of what an optimal heart rate might be and where increased health risks may begin.

Reducing heart rate is an accepted treatment goal for people with certain heart conditions, but it may also benefit people with hypertension and, preliminary research suggests, maybe even healthy people.

If your resting heart rate is at the high end of the normal range, and especially if it is over 100, you should talk to your doctor about your overall health and your other risk factors for heart disease. If you have a heart condition, you may already be on medication that lowers your heart rate.