Open Water Swimming

Turns out it’s maybe not so accurate for women.  According to a recent NYTimes article:

Last week, researchers at Northwestern Medicine in Chicago announced a new formula for calculating a woman’s maximum heart rate, a measure commonly used by athletes to pace themselves and monitor their progress. In a study of nearly 5,500 healthy women, scientists discovered that a decades-old formula for calculating heart rate is largely inaccurate for women, resulting in a number that is too high.

….

The commonly used formula subtracts a person’s age from 220. But based on the data collected in the Chicago study, the right formula for calculating a woman’s maximum heart rate is a little more complicated: 206 minus 88 percent of a woman’s age.

Yeah, whatever.  Maybe this obsessive training-by-numbers deserves a rethinking anyway. As the article also notes:

Of course, the new formula for women also raises new questions about the reliability of the old heart rate calculations for men. The original formula stems from research in the early 1970s that reviewed average maximum heart rates from 10 studies of men. The formula was a general calculation made for discussion purposes among academics, never intended to be used by the public.

However, the simplicity of the calculation appealed to a generation of exercisers who were looking for guidance about how hard to push themselves to improve fitness and improve their heart health. Companies promoting heart rate monitors, fitness clubs and family doctors all embraced the formula as a simple measure of fitness and the 220 minus age calculation became standard fitness advice.

But many researchers say it is ridiculous to base exercise goals on a person’s age rather than individual fitness level.

“The fitness industry, by attaching this to every treadmill ever made, kind of perpetuated this formula,” says Dr. Tim Church, an exercise researcher and director of preventive medicine at the Pennington Biomedical Research center in Baton Rouge, La. “There’s the idea that the formula was somehow not working out for women, but I’d make the argument that it doesn’t work out for anybody.”

In 2001, a University of Colorado team also concluded that the standard heart rate equation was inaccurate for both men and women. They devised a similar formula they said applied to both sexes — maximum heart rate equals 208 minus 0.7 times age — but the equation never caught on with the public.