Sigma Nutrition Radio #588: Menstrual Cycle "Syncing": Do the Claims Hold Up to Evidence? – Expert Panel
Dec 23, 2025
In this engaging discussion, Professor Kirsty Elliott-Sale shares insights on hormonal fluctuations and their impact on performance. Stu Phillips debunks myths around 'cycle syncing' and emphasizes that there’s no evidence requiring phase-specific nutrition. Eric Helms highlights that muscle gain is similar for men and women, with training efforts being the real drivers of hypertrophy. The panel advocates for personalized training strategies instead of rigid templates, urging better research to support female athletes.
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Menstrual Cycle Is Highly Variable
- The menstrual cycle is highly variable across women and cycles, not a fixed 28-day pattern.
- Estrogen and progesterone fluctuate differently, so phase-based assumptions are unreliable.
No Clear Recovery Differences By Cycle Phase
- There is no solid evidence that recovery differs across menstrual phases or between sexes.
- Small changes in HRV or heart rate don't justify different recovery protocols for women and men.
Auto-Regulate Rather Than Rigid Cycle Syncing
- Train according to how you feel rather than rigidly syncing sessions to cycle phases.
- Auto-regulate workload when symptoms or motivation vary, since individual responses differ.