That’s the word from Dr. Martha Gulati from Northwestern Medicine. She and a team of researchers have been working on a serious question for all women who exercise: how fast can our hearts really go? The answer? Well for women it’s not the 220 – age formula posted in your gym!
Men should still use the old formula, but women will need to do a little more math:
Peak heart rate for women = 206 – (88% x age)
A little math shows us that this formula gives us a lower answer than the men’s formula. “At age 50, the original formula gives a peak rate of 170 beats per minute for men and women. The new women’s formula gives a maximum heart rate of 162 beats for women.” For a 20 year old woman the difference is more striking: the old formula says she can get up to 200 bpm but the new formula says it’s only 188!
Where this really becomes important is during workouts. Women have long noticed that they have a hard time getting into the target heart rate “zone” for a cardiovascular workout of 55-85% of maximum heart rate. It turns out that the problem is we’re using the wrong maximum heart rate to make those calculations, and as a result we are working too hard to get the intended result. Our hypothetical 50 year old woman above may have been pushing hard to get towards 144 bpm — 85% of her “old” maximum heart rate — when she really should slow down if she gets over 138 bpm! Some authorities suggest that getting beyond 85% of maximum heart rate increases cardiovascular or orthopedic risk, which is exactly the opposite of what exercise should do.
The other place this is important is your doctor’s office. How your body responds to exercise is something a doctor considers when he is considering the possibility of cardiovascular problems. A doctor using the men’s formula for a woman may either suspect a problem where none exists, or worse yet miss a problem.
Unfortunately, much exercise research tends to treat women as small men despite the many differences between the sexes. The bottom line is that female athletes and all women who work out need to pay attention to how their bodies react to exercise, and consider the latest studies with a critical eye not only towards the data, but also towards the gender of the study participants.
