New Flo Health Research Suggests Women Don't Necessarily Need to Change How They Exercise Across Their Menstrual Cycles

Data from more than 5,000 women suggests that physical activity or exercise patterns among non-athletes vary little across the menstrual cycle

LONDON--(BUSINESS WIRE)--While the practice of tailoring workout type or intensity to specific menstrual phases — known as “cycle syncing” — has surged in popularity, new data from Flo Health (the #1 women’s health app worldwide) published in SAGE Women’s Health suggests that the menstrual cycle phase may have less influence on women’s everyday physical activity and exercise patterns than commonly assumed.

The study,“Exercise and physical activity changes during the menstrual cycle in users of the Flo app,” analyzed data from 5,700 app users to determine whether reproductive cycles are associated with significant changes in physical activity and energy output. Examining correlations between participants’ exercise logs, energy expenditure, step counts and menstrual tracking data, researchers concluded that while minor fluctuations in daily movement and workout energy expenditure were present, the scale of these differences were too small to be of consequence for non-professional athletes.

Workout frequency, however, showed somewhat greater variation across the cycle, with fewer workouts logged during bleeding days.

“We all want to get the most from our workouts, but it is important to understand what advice is worthwhile and what is misguided,” said Liudmila Zhaunova, PhD, Flo's Director of Science. “This research is challenging the need for an exercise regime built around your cycle phases. What matters far more is adapting it to your own symptoms, on the days you need to.”

The menstrual cycle involves substantial fluctuations in sex hormones, which may be associated with changes in energy levels and fatigue. Fewer workouts during bleeding days could be related to women experiencing symptoms such as cramps, pain, or low energy and choosing to skip workouts or other planned exercise on those days. In contrast, the relatively small variation in step counts and energy expenditure may reflect the fact that everyday activities—such as commuting to work, running errands, or caring for family—often continue regardless of menstrual cycle phase.

Key Research Highlights:

• Negligible Step Count Fluctuations: Step counts reached their peak in the late luteal phase and their lowest during bleeding days, but the total difference between these was roughly 2%.
• Consistent Energy Expenditure: The study found only a 5.2% difference in energy expended during gym sessions when comparing menstruation days to the early luteal phase, a deviation unlikely to impact overall health or fitness goals.
• Fewer Workouts Overall During Bleeding Days: Users logged the most workouts in the late luteal phase (26–29% of sessions) and the fewest on bleeding days (15–16%), but the same pattern held whether they were doing gym workouts, cycling, or running, with no difference in the number of logs by exercise type.
• Focusing on Symptoms over Theory: The findings suggest that individuals should adopt symptom-led guidance. Adjusting activity levels is valid when experiencing actual discomfort or fatigue, rather than following a theoretical phase-based plan.

In summary: this research shows that activity levels and workout energy expenditure remain relatively consistent across the menstrual cycle, although there may be a difference in how much people choose to work out, particularly on bleeding days. This suggests there may not be a need for a “cycle-synced” workout template aligned solely with the menstrual cycle, and that flexibility to adapt according to symptom burden is likely the better approach. Tracking your cycle and symptoms with Flo can help women take ownership of this.

What trends on social media are not always what holds up after research, so use educational resources such as those provided by Flo to ensure you are learning from facts, not fiction.

Survey Methodology

Between January 2023 and August 2025 step count and workout data was collected from 5,703 Flo app users aged 18 and over who logged at least one menstrual cycle with a positive ovulation test. Step count and workout measurements were recorded on the users’ own smartphones or wearable devices linked to the Flo app. Differences in step counts and energy expenditure were compared across cycle phases aligned to cycle start dates and ovulation test dates. The study was approved by the WIRB-Copernicus Group Institutional Review Board (IRB number: 20226050).

About Flo Health

Flo Health is the #1 Health and Fitness app worldwide and the #1 OB-GYN-recommended platform for period and cycle tracking. In 2024, Flo became the first European femtech unicorn following an investment from General Atlantic and now supports 80 million monthly active users (MAUs) worldwide. Powered by a network of over 100+ medical experts, Flo guides women through every stage of their health journey – from menstruation to conception, pregnancy, and menopause – offering curated cycle and ovulation tracking, personalized health insights, daily educational content, and a private community for users to share questions or concerns. Through its Pass it on Project, Flo has donated 28M Flo Premium subscriptions to improve health literacy to women in need, aiming to reach up to one billion. A leader in privacy and security, Flo Health's Anonymous Mode feature was recognized as one of TIME's Best Inventions 2023 and also named a finalist for Fast Company's 2023 World Changing Ideas Awards as part of the company's commitment to privacy.

For more information, please visit https://flo.health.