Should your period change how you exercise?

If you have been on social media recently, you might have seen the claim that women should sync their exercise to their menstrual cycles, a trend known as cycle syncing. The idea is that by matching workout type or intensity to the different stages of your menstrual cycle, you can get more out of training while accommodating menstrual symptoms.¹ This idea is based on the fact that hormone levels change over the menstrual cycle, causing swings in your mood, energy, or social engagement.² However, the existing scientific evidence to support cycle syncing itself is somewhat inconsistent and contradictory, lacking a clear clinical consensus. At Flo, we like to work with facts, so we put this hypothesis to the test with our scientific research team. 

And what did we find? Something that aligns with a belief we have long held at Flo: the menstrual cycle does not need to be a barrier to living your life or getting results. There is no need to build an exercise regimen around your cycle to maximize what you get out of it. What matters far more is adapting it to your own symptoms on the days you need to.

Over 5,000 members show very little difference

In the recent study published in the journal Women’s Health, we assessed over 5,000 Flo app members’ physical activity data, including step counts and energy expenditure, to investigate if the amount of daily steps and workouts undertaken by Flo members varies over different cycle phases. For this, the cycle phase was determined from member-logged period start and end dates and positive ovulation test date, identifying the five key phases of the menstrual cycle: bleeding days, midfollicular, fertile window, early luteal, and late luteal.

Our first observation was based on daily movement. This varied only slightly across the cycle, with median step counts ranging from 4,399 in the midfollicular phase (the lowest) to 4,491 in the late luteal phase (the highest), presenting a gap of 92 steps, or 2%. Once we took into account the differences between participants’ baseline activity, it reduced further to a difference of 85 steps between these phases, roughly 1.8%. To put these differences into perspective, 85 steps is about one minute of walking. 

Next, when looking at energy expenditure during logged workouts, the data told much the same story. Cycling and running showed no meaningful differences across the cycle at all, while gym sessions recorded 5.2% more energy expended (around 16.8 kcal) in the early luteal phase compared with bleeding days. Again, to put that into perspective, that’s fewer calories than a handful of grapes, making a barely noticeable difference. 

When we looked at workout frequency, we found that members did tend to log more gym, cycling, or running workouts in the late luteal phase (26% to 29% of all sessions) and the fewest on bleeding days (15% to 16%). This pattern was consistent across all three workout types, suggesting that the lower number of workouts logged during bleeding days was not specific to any particular type of exercise.

So what does it mean?

Overall, this research puts a popular cycle-syncing question to the test: Does your menstrual cycle really need to change how you exercise?

Our findings show that Flo members varied little in how much they moved or how they exercised across the menstrual cycle, but there was more variation in how often they chose to work out. Daily movement, measured by step count, remained almost consistent throughout the cycle. That may not be surprising: Everyday activities like getting to work, running errands, or looking after family often continue regardless of where you are in your cycle.

Among those who did exercise, workout energy expenditure also remained largely stable across cycle phases. In other words, when people chose to work out, they didn’t appear to substantially change how much energy they expended based on where they were in their cycle. What did change was workout frequency, with fewer workouts logged during bleeding days. One possible explanation is that symptoms such as pain, fatigue, or low energy may lead some people to exercise less often during this time.

“Hormonal fluctuations across the menstrual cycle can contribute to symptoms such as fatigue, pain and changes in energy, which may affect how women feel about exercising,” says Erica Rauff, PhD, co-author and Flo medical expert board member. “Listening to your body is important and movement can still be beneficial across all menstrual cycle phases. However, on days when your symptoms are more noticeable, you may want to choose a lower-intensity activity or take a rest day. There’s no one-size-fits-all approach to exercise across the menstrual cycle,” recommends Rauff, Associate Teaching Professor of Biobehavioral Health Director, Penn State University. 

So, rather than supporting a one-size-fits-all workout schedule based solely on cycle phase, our findings point toward a more individual approach. Menstrual cycles are personal, and how you exercise around them can be too. Tracking your cycle and symptoms can help you understand when lower-energy or higher-pain days tend to occur. That way, you can adjust your activity when you need to, not simply because a particular cycle phase says you should.

In short: Listen to your body, track your cycle and symptoms, and do what feels right for you. If you feel good and want to go on that run, go on that run. And remember, trends on social media don’t always hold up to the data; look to evidence-based resources, including Flo’s educational content, to help separate fact from fiction.

1. Pfender, Emily J., et al. "Cycle Syncing and TikTok's Digital Landscape: A Reasoned Action Elicitation Through a Critical Feminist Lens." Qualitative Health Research, vol. 35, no. 10–11, 22 Nov. 2024, pp. 1191–1203, https://doi.org/10.1177/10497323241297683.
2. Cleveland Clinic. "Nutrition and Exercise Throughout Your Menstrual Cycle." Cleveland Clinic Health Essentials, 26 June 2026, https://health.clevelandclinic.org/cycle-syncing.