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In one of the largest studies of its kind, Harvard’s Apple Women’s Health Study found that participants with regular menstrual cycles exercised more minutes per day, on average, than participants with irregular cycles — 20.6 minutes versus 18.6 minutes daily.
Inside the Apple Women’s Health Study
Published in May 2025, this analysis drew on data from 110,740 participants ages 18 to 50 who consented to sharing Apple Watch and survey data. Researchers analyzed 22.85 million logged workouts across 461,163 collective cycle days, using data collected between November 2017 and February 2025.
The scale of this dataset is part of what makes it notable — most prior research on exercise and menstrual cycles relied on much smaller samples, often just a few hundred participants. A dataset of this size makes the patterns researchers found considerably more reliable.
What They Found
Participants with regular cycles averaged 20.6 minutes of exercise per day. Participants with irregular cycles averaged 18.6 minutes per day — a modest but statistically notable gap. Notably, the researchers pointed out that irregular cycles can be caused by many factors, some of which may make it harder to exercise consistently, suggesting the relationship likely runs in both directions.
Correlation, Not a Guarantee
This finding doesn’t prove that exercise alone regulates cycles. It may partly reflect that women managing conditions that cause irregularity, like PCOS, thyroid issues, or high chronic stress, also face more barriers to consistent movement, from fatigue to unpredictable symptoms. Still, exercise’s broader, well-documented benefits, including improved insulin sensitivity, make it a reasonable and evidence-backed lever to focus on regardless of cause.
What Type of Exercise Did Regular Exercisers Do?
Across all participants in the study, the top three most-logged exercise types were walking, cycling, and running — accessible, low-barrier forms of movement rather than extreme or highly specialized training.
It's also worth noting what the study didn't find: a dramatic difference in exercise minutes between the two groups. A roughly two-minute daily gap is meaningful at a population level, but it's not the kind of gap that suggests women with irregular cycles need to overhaul their entire routine — small, sustainable increases in daily movement are the realistic takeaway.
The Numbers
- 110,740 participants tracked
- 20.6 minutes/day — average exercise for regular-cycle participants
- 18.6 minutes/day — average exercise for irregular-cycle participants
- Walking, cycling, and running were the top 3 logged activities
Movement and Your Cycle Go Hand in Hand
Exercise habits and cycle regularity clearly move together, even if the exact cause-and-effect isn't fully settled yet. Whatever your current routine looks like, small, consistent movement — paired with a daily cycle essential like PumPums Daily Cycle Essentials for the harder days — is a realistic way to start building a more regular rhythm.
