New Research Leads to New Target Heart Rate Formula

Forget what you know about calculating your target heart rate because scientists say the math just doesn’t add up. According to a new study, the formula used to calculate peak heart rate is flawed because the original research left out an important population group: women.

The traditional formula of subtracting your age from 220 has been in use for over forty years. People plug this number into heart rate monitors so they know how hard they should work when they are exercising. Doctors use it to figure out how hard a patient should exercise when they are diagnosing heart conditions during a stress test.

A Fresh Look at Old Results

For the new study, researchers analyzed over 25,000 stress tests completed between 1993 and 2006 by men and women 40 to 89 years old. What they found were significant differences in how men and women’s hearts respond to exercise.

The study showed that while everyone’s heart rate declines with age, the decline is more gradual in women. This means the old formula overestimates the peak heart rate younger women can reach (good news for this group!) but underestimates the peak heart rate of older women (bad news for this group).

The study also found that younger men have a lower resting heart rate and higher peak heart rate than women. Their heart rate also rises more dramatically during exercise than women, but even so, it returns to normal levels more quickly when exercise is stopped. The reasons for these differences aren’t clear but most likely it has to do with sex hormones.

So What Should Your Target Heart Rate Be?

To account for these gender related nuances, the scientists developed two new formulas: one for men and one for women aged 40 to 89. Women should use the formula 200 minus 67 percent of their age, and men should use the formula 216 minus 93 percent of their age. Gone are the days of doing this calculation in your head, unless of course you are some sort of math genius.

But what if you are a woman who is less than 40 years old? Unfortunately there isn’t an answer to this yet and the relationship of heart rate to age may be different. There just aren’t enough studies available to provide good results.

Change is good, especially if it can help doctors to more accurately diagnose heart-related conditions. If you fall within the 40 to 89 year old age group, grab a calculator and get to work. If you are less than 40 years old, instead of aiming for a specific target heart rate number, consider focusing on your post-workout recovery time: the faster your heart returns to a resting rate the fitter you are becoming.