Healthy Outlook Blog

And because doctors have been using the same calculations to assess women’s heart disease risks on the basis of stress tests, some women probably have been told that they’re at higher risk than they really are.

Target heart rate is the “zone” between 50 percent and 80 percent of maximum heart rate, which is figured by subtracting your age from 220 and is the number at issue.

Like a lot of other things in medicine, the formula for calculating maximum heart rates was developed from studies in men. It goes back to the 1970s. Martha Gulati, M.D., director of women’s cardiovascular health at The Ohio State University, says she was “kind of shocked that this formula was guiding all of us and that the original studies didn’t include women.” So she set out to learn what is normal for women and arrived at a whole other calculation that pertains not only to exercise but to stress tests.

“Now we know what’s normal for women, and it’s a lower peak heart rate than for men,” she says. Dr. Gulati and her team developed the new gender-specific formula on the basis of an analysis of information from nearly 5,500 healthy women ages 35 and older who were enrolled in the St. James Women Take Heart Project in progress since 1992 in the Chicago area.

The new formula is a little trickier to use and harder to remember than the old one: women must subtract 88 percent of their age from 206. Unless you’re a math whiz, you’ll probably need a calculator, but Dr. Gulati says you only have to run the numbers once a year …on your birthday.

CONNECT THE DOTS

Visit The Ohio State University Newsroom to read more about Dr. Gulati’s recommendations for new female-focused stress test guidelines, which she is helping to write. To find out whether you’re in your target heart rate zone during exercise, take your pulse in your carotid artery.