For longevity, women need only half as much exercise as men, study finds

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It’s well-established that exercise can help you live a longer and healthier life. Now, a new study suggests that women may require less exercise to get similar longevity benefits as men.

The finding is striking because physical activity guidelines for American adults are the same for men and women. But partially because of differences in size, muscle mass and lean body mass, it appears that women can make big gains in longevity while doing about half the exercise men need to do to get the same benefit.

  • For men, the peak “survival benefit” comes with 300 minutes a week of moderate to vigorous exercise. When men exercise this much, they had an overall 18 percent lower risk of dying than inactive men.
  • Women only have to exercise 140 minutes a week to lower mortality risk by 18 percent. If women exercise 300 minutes a week, they lower their risk by 24 percent.
  • Men got the most benefit if they did three sessions a week of muscle strengthening activity compared with women, who got equivalent benefit from one muscle strengthening session a week.
  • In the United States, only about a quarter of adults have met the recommended physical activity guidelines of at least 150 to 300 minutes of moderate-intensity aerobic exercise and two muscle-strengthening activities a week, with men more likely than women to meet the recommendations across all age groups.

“Being physically active matters, and it seems to influence overall survival,” said Martha Gulati, the director of preventive cardiology in the Smidt Heart Institute at Cedars-Sinai and a co-author of the study, which was published in the Journal of the American College of Cardiology. “But small amounts can go a long way, and in fact, for women, smaller amounts can go a longer way than they can for men.”

To conduct the new study, researchers looked at more than 400,000 U.S. adults who provided survey data on leisure-time activity from 1997 to 2017 and compared that data with death records. There were nearly 40,000 all-cause deaths, including approximately 12,000 cardiovascular deaths, during the follow-up period. But in looking at differences between men and women, it became clear that women gained greater longevity benefits from exercise.

The explanation may lie in physiology, experts say.

“Men require more exercise partially due to the fact that they have greater muscle mass and greater lean body mass,” Gulati said. “And so when they exercise, the benefit to the whole body, including the muscles, requires a greater duration.”

Gulati added that men, on average, have proportionately larger hearts and muscle fibers than women, but that women have a higher density of capillaries per unit of skeletal muscle compared to men.

“They’re increasing the blood flow sooner than men with smaller amounts of exercise,” she said.

Mercedes Carnethon, a professor and vice chair of preventive medicine at Northwestern University Feinberg School of Medicine, agrees that the physiological differences between the sexes can help explain the findings. She was not involved in the new study.

“There are structural differences in the hearts between men and women, so men’s hearts tend to be a bit more efficient,” Carnethon said. “There are essentially differences in the potential for gaining fitness.”

Gulati hopes that the findings in this study can help close the “gender gap” in exercise by motivating women to engage in regular leisure-time physical activity. According to the National Center for Health Statistics, 28.3 percent of men meet national exercise guidelines, while just 20.4 percent of women do.

“Whenever somebody gives you guidelines that are identical for men and women, at least as a physician and somebody who studies sex differences, my antenna always will go up,” she said. “I will always ask: ‘What is it based on? How can we be the same?’”

What people are saying about the study

Ulrik Wisløff, the head of the Cardiac Exercise Research Group at the Norwegian University of Science and Technology in Trondheim, said that the new study’s data “fits perfectly” with what his has seen in his own studies that have found that women need less exercise than men to get protection against lifestyle-related diseases and premature death.

“Their data are of high interest to me, and it is an area that has been overlooked for too long,” said Wisløff, who was not involved in the new study.

While the longevity benefits of physical activity for men and women are more similar at a low amount of physical activity, the sex differences emerge at higher doses of exercise, the authors of the new study say.

A 2011 Taiwanese cohort study of 416,175 individuals — 199,265 men and 216,910 women — found that both sexes had a 14 percent reduced risk of all-cause mortality and a three-year-longer life expectancy with as little as 15 minutes of moderate-intensity activity per day, or around 90 minutes per week, compared with the inactive individuals.

But a 2011 meta-analysis of 33 studies observed that the relative risk for coronary heart disease was approximately one and a half to two times lower for women who met the basic exercise guidelines compared with men at similar levels of physical activity.

Limitations of the research

One major limitation in the study is that participants’ physical activity was not tracked and therefore researchers could not confirm their self-reported data. The survey also only accounted for leisure-time physical activity.

“It didn’t include the activity that we do in our daily lives, walking to work, walking to our car, gardening, cleaning the house, chasing our children, all those things were not accounted for,” Gulati said.

Differences in male and female life expectancy “didn’t explain the observation,” said Keith C. Ferdinand, the Gerald S. Berenson chair in preventative cardiology at Tulane University School of Medicine, who was not involved in the study. “It’s not simply because the women live longer.”

Gulati doesn’t think this study’s findings will change any physical activity guidelines, but she hopes it encourages researchers to look further into the data so that experts can have a better understanding on what to prescribe to patients.

“I think the message to people, though, is that a small amount of activity goes a long way,” she said.

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