A common assumption is that people who weigh less are more fit. And, among men and women ages 30 and older, cardiovascular fitness does tend to decline as body mass index increases. For younger adult women, however, this may not be the case, according to preliminary research findings based on patients at the Cardiovascular Performance Program at Massachusetts General Hospital. Woman under 30 with BMI levels in the upper range of optimal had the highest levels of cardiovascular fitness, even when compared with thinner, leaner women of the same age, according to the large Harvard University study.

“This serves as a reminder that low BMI is not a prerequisite for higher aerobic fitness,” said co–senior study author J. Sawalla Guseh, MD, instructor in medicine at Harvard Medical School and a cardiovascular physician scientist. “Given the risks that can come with weight loss in athletes, and given that there are many other variables an athlete can adjust to maximize performance—such as training intensity, training frequency, skill acquisition, competition strategy, sleep and nutrition—we advocate that BMI and weight as targets should be de-emphasized for young adult women.”

The research was presented at the American Heart Association’s virtual Basic Cardiovascular Sciences 2020 Scientific Sessions. To learn more, go to bit.ly/3nwaNlD.

See also: BMI Proves Unreliable in Certain Populations