Menstrual cycle and training: what the evidence actually supports
Exercise professional · creator of the Letz method
Short answer
A systematic review and meta-analysis found that menstrual cycle phase has a trivial effect on performance on average, alongside low-quality evidence and substantial individual variability. This does not support periodizing training by cycle phase as a general rule, but it does not invalidate individual experience.
What the review found
The question was investigated in a systematic review and meta-analysis: does exercise performance vary across the menstrual cycle? The average effect found was trivial, and the quality of the underlying evidence was rated as low.
A trivial effect on average does not mean "nothing happens to anyone." It means there is no pattern consistent and strong enough to warrant population-wide guidelines.
Why products sell the opposite
An entire industry of apps exists that periodize training by cycle phase, making specific promises. This practice is not supported by the effect sizes found in the literature.
Selling a rigid framework based on a trivial effect turns statistical noise into a product—and, in practice, tells someone to train less during a phase in which they might feel completely fine.
What makes sense instead
Individual variability is precisely why autoregulation makes more sense than a calendar. Adjusting load and volume based on daily perceived exertion captures whatever is occurring—whether from the menstrual cycle, sleep, or stress—without needing to pin down a single cause.
If someone consistently notices a pattern in their own history, that is their own real data and worth using. What is not supported is imposing an average pattern on everyone.
Frequently asked questions
Should I train less during menstruation?
Not as a general rule. The average effect of cycle phase on performance is trivial, supported by low-quality evidence. Adjusting based on how you feel each day is more defensible than adjusting by a calendar.
Do apps that periodize training by cycle phase work?
The practice is not supported by the effect sizes reported in the literature. Individual variability is too large for a fixed framework.
So the menstrual cycle does not affect anything?
It affects people individually, and symptoms are real. What the evidence does not support is an average performance pattern strong enough to prescribe training by phase.
Registry rules cited here
- Menstrual Cycle and PerformancePerformance may be slightly lower during the early follicular phase, but the effect is trivial and highly variable; the recommended approach is individualized, not a rigid phase-based rule.
- Training response varies widely between individualsFollowing the same program, gains in strength and muscle mass range from negligible to substantial; study averages do not predict an individual's response.
- Load and Volume AutoregulationRIR/RPE and objective measures can help adapt resistance training to daily fluctuations within a structured plan.
- Monitoring recoveryRecovery should be tracked using simple, frequent measures such as perceived exertion, sleep, and mood; heart rate variability works better as a weekly trend than as a single daily figure.
Sources cited
- McNulty et al., Sports Medicine, 2020 DOI 10.1007/s40279-020-01319-3
- Ahtiainen et al., Age, 2016 DOI 10.1007/s11357-015-9870-1
- Larsen et al., Sports Medicine - Open, 2021
- Greig et al., Sports Medicine, 2023
- Zourdos et al., Journal of Strength and Conditioning Research, 2016 DOI 10.1519/JSC.0000000000001049
- Kellmann et al., International Journal of Sports Physiology and Performance, 2018 DOI 10.1123/ijspp.2017-0759
- Plews et al., Sports Medicine, 2013 DOI 10.1007/s40279-013-0071-8
Informational content about training and nutrition. It is not a recommendation, prescription or adjustment of any medication, and it does not replace assessment by your doctor or dietitian.