How much exercise does it take to protect an aging heart? A sweeping analysis of wearable data suggests the answer may differ sharply for men and women. For men over 50, the bar to match women’s heart benefits may be more than twice as high.
What the wearable data shows
In a study published in Nature Cardiovascular Research, scientists analyzed wrist-worn accelerometer data from the UK Biobank to track how weekly activity levels correlated with coronary heart disease (CHD) outcomes over nearly eight years. They examined 80,243 adults free of CHD at the start (average age 61) and 5,169 adults already living with CHD (average age 67), then linked movement patterns with new CHD events and deaths.
The headline finding is stark. To reach roughly a 30% reduction in CHD risk, women needed about 250 minutes per week of moderate to vigorous physical activity (MVPA), while men needed about 530 minutes per week. That is close to nine hours for men versus just over four hours for women—both achievable targets, but with a clear sex gap in how much exercise translates into comparable protection.
Even at the commonly recommended threshold of 150 minutes per week, benefits were evident. Women who met that mark had an estimated 22% lower risk of developing CHD than those who did less, while men saw a 17% lower risk. Among adults already diagnosed with CHD, smaller time commitments appeared to matter: women accrued a meaningful mortality risk reduction with about 51 minutes per week of MVPA, compared with about 85 minutes for men.
These dose–response curves, generated from objective, weeklong accelerometer measurements, reinforce a central theme: more movement confers more benefit for everyone, but women tended to gain more risk reduction per minute of activity than men. The patterns held across multiple sensitivity analyses designed to stress-test the results.
Why the gap may exist
Current public health guidelines from major bodies such as the WHO and American Heart Association recommend the same baseline target—at least 150 minutes per week of MVPA—for both sexes. Yet physiology is not identical, and the new analysis points to meaningful differences in how bodies respond to the same exercise dose.
The authors suggest several biological factors could be at play. Higher estrogen levels may enhance fat burning during exercise, shifting metabolism toward fuels that favor cardiovascular health. Women also tend to have a greater proportion of type I, endurance-oriented muscle fibers, which are more oxidative and may respond differently to sustained activity than the more glycolytic muscle profile typically seen in men. These hypotheses require more mechanistic study, but they align with known sex differences in metabolism and muscle physiology.
“This isn’t bad news for men, it’s just something we should know about,” said Nir Eynon of Monash University, speaking to New Scientist. “Once we know, we can do better – we can do more exercise. And while it’s reassuring for women who are busy all the time, I also think women should not miss the fact that they need to exercise as well.”
Cardiologist Ersilia DeFilippis of Columbia University praised the rigor of the work while noting a crucial caveat: the UK Biobank cohort is predominantly white and relatively well-off. That makes it essential to test whether the same dose–response patterns hold in more diverse populations with higher baseline cardiovascular risk.
“Understanding how these findings apply to a more racially diverse and socioeconomically disadvantaged population will be imperative in the future, given their higher burden of cardiovascular disease,” DeFilippis said, calling the study “robust” and arguing it underscores the need for sex-specific guidance.
“It’s never too late to start moving and be more active.”
How much is enough? Key numbers to know
- To cut incident CHD risk by about 30%: women around 250 minutes/week of MVPA; men around 530 minutes/week.
- For adults living with CHD, to reach a comparable mortality risk reduction: women about 51 minutes/week; men about 85 minutes/week.
- Meeting 150 minutes/week still helps: an estimated 22% lower CHD risk for women and 17% lower for men versus doing less.
- Moderate-to-vigorous activity includes brisk walking, cycling, swimming laps, stair climbing, or any movement that noticeably raises breathing and heart rate.
- Consistency matters: the study also found risk declined as the number of days per week meeting daily targets increased.
Important caveats
This was an observational study, so it cannot prove cause and effect. The researchers controlled for a wide range of factors—age, body mass index, smoking, alcohol use, sleep, diet quality, comorbidities, and more—and repeated analyses in different ways, with similar results. Still, unmeasured confounders are possible.
Generalizability is another limitation. UK Biobank participants are not a perfect mirror of the general population; they skew healthier, wealthier, and are about 93% white. As DeFilippis notes, verifying these dose–response patterns across racial and socioeconomic groups is essential, particularly because cardiovascular disease disproportionately affects disadvantaged communities.
Finally, activity was measured by wrist-worn accelerometers and classified into MVPA using established acceleration thresholds. That method captures real-world movement objectively, but it may not perfectly distinguish activity types or intensities in every individual. Even so, it avoids the recall bias of self-reported exercise and provides a strong foundation for dose–response insights.
What this means for patients and policy
One-size-fits-all exercise guidance is simple to communicate, but this study adds weight to a more personalized view. For heart protection, older men may need to aim higher than the standard minimum, while women may harvest outsized benefits from hitting or modestly exceeding guideline levels. That does not mean men are doomed or women can coast; it means the same prescription may land differently across sexes.
For clinicians, the message is practical: tailor exercise prescriptions with sex, age, and health status in mind, and use wearable data when possible to set realistic, trackable targets. For public health leaders, the findings bolster calls for sex-specific recommendations—or at least sex-specific messaging—while cautioning that equity and access to safe spaces for activity remain critical.
Above all, the curves in this study bend in the same direction for everyone: every additional chunk of weekly movement lowers risk. Minutes can be stacked throughout the week, intensity can vary with fitness and mobility, and brisk walks still count. Even if the finish line differs by sex, the path forward is the same—keep moving, keep building, and let consistency do the quiet, cumulative work of protecting the heart.