Cardiologists emphasize that the comparison isn’t between men and women—but between people who move and those who don’t. “It’s showing that a woman who exercises compared to a woman who doesn’t exercise—the relative benefit appears greater than if you take a man who exercises compared to a man who doesn’t exercise,” says Carolyn Lam, a women’s heart health cardiologist and senior consultant at the National Heart Centre of Singapore, was serving as deputy editor at JACC when this paper was published. “The comparisons are within sex, not between sex.”
More recently, a 2025 study in Nature echoed these findings using wearable data from more than 85,000 participants in the U.K. to assess coronary heart disease (CHD) incidence. Women who met the 150-minute-per-week physical activity guideline had a 22 percent lower risk of CHD, compared to 17 percent for men.
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As weekly activity increased, the gap widened further. With 250 minutes of weekly movement, women’s risk dropped 30 percent, while men needed 530 minutes to see the same reduction. They also observed lower mortality risk among patients with existing CHD.
Taken together, these findings suggest that current exercise guidelines may not fully capture how different bodies respond to physical activity—and that researchers are only beginning to understand why. Scientists also found that women typically underreport exercise compared to men, so they ran a secondary analysis to account for this and found similar results.
Why might women benefit more?
Researchers don’t yet fully understand the mechanisms, but Lam says cardiologists have a few theories. “The mechanisms likely involve multiple systems working in concert,” she says. That could include larger boosts in HDL (the “good” cholesterol), improved blood vessel function (endothelial function), and more efficient metabolic adaptations with each workout.
One likely contributor is estrogen. “There are data that show that estrogen, the woman’s sex hormone, has some cardioprotective effects,” says Lam. “It could amplify the effects of exercise on these adaptations in our blood vessels and the heart.”
A 2017 literature review explains that estrogen (specifically estradiol, or E2) helps protect the heart by improving blood flow and reducing damage. It does this by encouraging the growth of new blood vessels (angiogenesis), increasing blood flow through vasodilation, and lowering harmful byproducts, such as oxidative stress and inflammation, which can damage tissues and organs, including the heart.
That said, this doesn’t mean women should jump to get on hormone therapy. “These are postulations,” she emphasizes. “And prospective studies haven’t proven that hormone replacement therapy provides this benefit.”
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