Feb. 20, 2024 -- Working out benefits us all -- but women might reap more benefits from grabbing a pair of dumbbells or taking a sweaty stroll than their male counterparts.
That's according to a large new study that found women who spend the same amount of time on a treadmill, playing pickleball, or just taking a brisk walk get more lifesaving benefits from the exercise than men. The findings suggest that the nation’s current one-size-fits-all exercise recommendations may instead better reflect the benefits of exercise using sex-based guidelines.
The study, published Monday in the Journal of the American College of Cardiology, found that exercise can reduce women’s risk of early death by up to 24%, while men who exercised for the same amount of time only reduced their risk by 15%.
The risk reductions were similar when the researchers looked only at deaths resulting from problems with the heart or blood vessels, which include the nation’s leading causes of deaths like heart disease and stroke. Again, women’s benefit from exercise was greater than men’s, with regular exercise reducing the risk of a fatal heart attack, stroke, or other heart event by 36% for women, but by just 14% for men.
“There are so many busy women who just have a lot on their plate. They are caretaker of the household, maybe have a job outside of the household, maybe have kids, and are really, really busy. This study lets them off the hook,” said the study’s senior author, Susan Cheng, director of the Institute for Research on Healthy Aging at Cedars Sinai in Los Angeles. “You don’t have to feel guilty about not exercising three to five times a week because it turns out you can actually do less.”
Cheng and her colleagues found that women who engaged in 140 minutes of weekly physical activity reduced their risk of early death by 18%, while men had to do 300 minutes -- more than double -- to experience the same 18% risk reduction, compared to people who were less physically active.
But putting in more than that amount of time can lead to greater protective benefits for women, said Cheng.
The benefits varied based on the intensity and weekly minutes of physical activity, but women always experienced greater protection than men no matter the type, intensity, or duration of exercise:
- Women’s maximized benefit from moderate exercise like brisk walking or gardening topped out at 300 minutes per week with a 24% reduced risk of early death.
- Vigorous workouts like running or swimming laps reduced the risk of early death by 19% in men based on 110 minutes per week, while women reduced their risk by 19% with 57 weekly minutes (and just 13 additional vigorous minutes brought the protection to 24%).
- Women also experienced greater reductions than men in the risk of early death from regular muscle-strengthening workouts.
The researchers arrived at their conclusions after analyzing survey data from 1997 to 2017 collected from more than 400,000 people who self-reported their leisure-time physical activity habits. About 55% of the survey respondents were women.
The average age of the people in the study was 44 years old (their ages ranged from 18 to 85). The researchers then linked the people in the surveys to a national database of people who have died and analyzed their causes of death in relation to their reported exercise habits.
The study excluded people who already were diagnosed with heart disease or who previously had a heart attack or stroke. Those with emphysema, chronic bronchitis, or cancer were also excluded.
The findings lack some certainty because the exercise was self-reported on a survey and not confirmed by data from people wearing fitness tracking devices, said Emily Kraus, MD, a physical medicine and rehabilitation specialist and assistant professor at Stanford Medicine in California. She was not involved in the study.
Nevertheless, Kraus lauded the research paper because it helps draw attention to the scientific gaps in knowledge about sex-based differences when it comes to exercise.
“I was excited to see a study focusing on sex-specific differences, but I have more questions than answers after reading it, partly just because of the nature of this type of study. It provides some large, higher level, and population-based information, which is important to guide us into future research as well as potential policies or changes to guidelines,” said Kraus, who directs Stanford’s FASTR Program, which is part of an initiative to close the gender gap in sports science research.
“What was interesting to me was learning more about what they call their gender gap, which was about the gap in physical activity and exercise, with men exercising more than women,” she said.
It’s a gap that begins during childhood and adolescence. National guidelines call for children ages 6 and up to get 60 minutes of physical activity per day, but just 15% of girls ages 6 to 17 years old and 31% of boys met the criteria in 2019, according to a CDC report.
In this latest study, 33% of women reported exercising 150 minutes or more per week, while 43% of men said they did so. (National guidelines for adults recommend 150 minutes of weekly physical activity for adults, no matter their gender.)
“Is it possible that we just have more sports activities for boys than for girls? Historically, yes, but that is changing and it’s improving. But is it also possible,” said Cheng, “that, biologically, female versus male physiology tends to want to engage in physical activity differently?”
Both Cheng and Kraus said these latest findings make sense because of known differences between men and women -- such as heart size or the blood’s capacity to transport oxygen -- that can dramatically affect physical performance. Cheng says her team’s findings point toward fundamental sex differences in cardiovascular aging.
“Should we really be putting everybody on the same scale in terms of the amount of time, the speed at which you run, the number of push-ups, the number of sit-ups, should that all be measured the same?” said Cheng, noting that some other countries like Canada and European nations already have sex-based fitness goals.
Another sign of differences in aging between men and women was a preliminary analysis by Cheng’s team that showed that older women in their menopausal years didn’t derive quite as much protective benefit from exercise as younger women. Essentially, the gap in benefits from exercise between men and women narrows as people age.
Both Cheng and Kraus said the goal is to offer people personalized exercise prescriptions. Kraus said she expects those prescriptions will change throughout the course of a person’s life.
“Think of all of the different phases of life that women experience that men do not,” said Kraus, “from the onset of a menstrual cycle to pregnancy to perimenopause, and how should those recommendations change to factor in those really physiologic and hormonal differences in an exercising woman?”
In a commentary published alongside the study, Wael Jaber, MD, and Erika Hutt, MD, both of Cleveland Clinic, wrote that the findings of this latest study may provide motivation for women to get moving.
“This may encourage physically inactive women to engage more in leisure-time physical activity given a more achievable goal in those women who believe that time is a barrier to exercise,” Jaber and Hutt wrote. “In addition, it may motivate physically active women to increase their exercise engagement given the substantial reduction in all-cause mortality and cardiovascular mortality of up to 24%.”
