How to Exercise with PCOS (Do You Train by Your Cycle?)

By Dr. Mélanie DesChâtelets, ND. Licensed naturopathic doctor and founder of PMOS Health Collective.

If you’re figuring out how to exercise with PCOS, you’ve probably hit the cycle-syncing trend: train a certain way in each phase of your cycle. It sounds scientific and empowering, and women genuinely deserve research built for their bodies. But my honest worry is that it slows some people down. So here’s what the research actually says about training across your cycle, the HIIT myth answered, and where to actually start, without adding more rules to your life.

One quick note. This is education, not medical advice, and I’m not your naturopathic doctor. Read it, take notes, then bring it to your own care team.

▶ Liked this video? Subscribe on YouTube.

Where cycle syncing gets it right

It’s right that the research has real gaps. Most exercise physiology was done on men, and even many studies on women estimate cycle phase by the calendar rather than by hormone testing or the body’s own signs and clues, which weakens the conclusions. So yes, we need more and better research for women. As exercise physiologist Dr. Stacy Sims, PhD, puts it, “women are not small men.” We metabolize, recover, and respond to fuel and stress differently, and that deserves attention. No argument from me there.

Is training by your cycle really personalized?

Here’s the irony. In the name of personalization, cycle syncing breaks the cycle into tidy boxes and then tells everyone to do the same thing at the same time. That’s not personalization, that’s templating, and it assumes your cycle is the number one predictor of your performance and that you feel the same every month. Think of the variation in your own cycles. And what about life? The toddler who wakes you at 2 a.m., the deadline that ate your sleep, the iron that’s low again. Your cycle is one input. So is your sleep. So is your stress. So is your capacity. So is context.

What the research actually says

A large review of 51 studies in women with regular cycles (which may not extrapolate to PMOS (formerly PCOS), where cycles often aren’t regular) concluded performance might be trivially reduced in the early follicular phase, roughly day one to five, basically your period. “Trivial” is the operative word. In the clinic we separate statistically significant from meaningful: it may be true that some women perform slightly worse on their period, but if you got eight bicep curls instead of your usual ten, do we actually care? A 2023 critical review out of McMaster University found an absence of high-quality evidence for programming resistance training around cycle phase. The honest takeaway: a hint of slightly lower performance on your period in some women, and that’s it. None of these say “don’t care.” They say ask her, the individual.

The outcomes that actually matter

Let me flip the tone. At a population level, we’re trying to get adults to 150 to 300 minutes of exercise a week, and the outcomes tied to hitting those targets aren’t “two extra reps.” They’re body composition, all-cause and cause-specific mortality, and disease progression in conditions like hypertension and type 2 diabetes. People who hit those targets literally live longer. So I genuinely don’t care if once in a while I lift eight times instead of ten because I listened to my body. Even Dr. Stacy Sims, PhD, once a “train by your cycle” voice, has shifted to “train by your readiness,” because so many things feed readiness. Not rules, not restrictions, just informed flexibility.

Should you avoid HIIT with PCOS?

One claim I see a lot: skip high-intensity interval training because it raises cortisol, and high cortisol can worsen insulin and therefore PMOS. Here’s what the research actually shows. Yes, intense exercise raises cortisol, but it rises and then comes back down, our bodies are built to be adaptable. And when HIIT is studied specifically in PCOS, it improves insulin resistance, inflammation, and menstrual frequency, the outcomes we actually care about. So I don’t worry about a temporary cortisol bump and leap to assumptions when the measured outcomes are clearly positive. And to be clear, HIIT isn’t mandatory. Non-HIIT, moderate exercise is beneficial too, so don’t let any of this pull you away from the real goal: 150 to 300 minutes a week, in whatever form you’ll actually keep doing.

Where to actually start

Don’t let the conversation get more complicated until you’ve mastered level one: consistency. Get to 150 to 300 minutes of moderate movement a week, plus about two weight sessions. Don’t make it harder than that. Your number one job is finding what makes you want to show up, because in the long run attendance matters more than anything else. I like a Good/Better/Best approach: an easy version for a hard week, an average goal for an average week, a stretch goal for a strong one. Keep it personal, and remember it’ll rarely be a single input that decides everything.

Watch the full video: Cycle Syncing vs. Science: Should You Train by Your Period?, and subscribe to my YouTube channel.

This article is educational, not medical advice or a diagnosis. If something here resonates, bring it to your healthcare team, who can look at it through the lens of your individual health.

Main references

1. McNulty KL, et al. The Effects of Menstrual Cycle Phase on Exercise Performance in Eumenorrheic Women: A Systematic Review and Meta-Analysis. Sports Med. 2020. PubMed
2. Colenso-Semple LM, et al. Current evidence shows no influence of women’s menstrual cycle phase on acute strength performance or adaptations to resistance exercise training. Front Sports Act Living. 2023. PubMed
3. Teede HJ, et al. Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. J Clin Endocrinol Metab. 2023. PubMed