Does the menstrual cycle affect elite performance? A meta-analysis found no signal.

Whether the menstrual cycle meaningfully affects athletic performance has become a more prominent question in elite sport in recent years, as more women's teams and federations invest in cycle-tracking programs. A systematic review and meta-analysis published this month in Reproduction and Fertility looked specifically at whether the evidence backs that up for one key performance measure — and found the current data doesn't show a significant effect [s1].

What the review required

The researchers set a strict bar for inclusion: studies had to confirm which menstrual cycle phase a participant was in through actual serum or plasma hormone analysis — not just calendar-based estimates, which the sports-science literature has increasingly flagged as unreliable — and had to involve elite or well-trained athletes rather than recreationally active or untrained participants [s1]. That requirement narrowed the eligible literature considerably, ultimately leaving five studies for the core meta-analysis, which compared maximal oxygen uptake (VO2 max) between the early follicular and mid-luteal phases of the cycle [s1].

What the pooled data showed

Across those five hormone-confirmed studies, the meta-analysis found no statistically significant difference in VO2 max between the early follicular and mid-luteal phases [s1]. There was a small, non-significant decrease in performance observed during the early follicular phase [s1] — a trend in the data, but one that didn't reach the threshold researchers use to call a finding reliable rather than likely noise.

Why the researchers aren't calling this settled

The paper is careful not to overstate a null result into a definitive "no effect" conclusion. The authors note that biological plausibility — the hormonal mechanisms that could plausibly affect performance are well understood — combined with athletes' own reported experiences, suggests that minor or individual-specific effects of cycle phase on performance may still exist, even though this pooled analysis didn't detect one at a statistically significant level [s1]. That's a meaningfully different claim than "the menstrual cycle doesn't affect performance" — it's closer to "the current evidence base is too small and too variable to detect an effect that might be real but modest, or that might vary meaningfully from athlete to athlete."

Why the evidence base is so thin

Five studies meeting a hormone-confirmed, elite-athlete standard is a small number for a question this widely discussed, and the review's authors point to that gap directly: they call for future research using standardized protocols, larger cohorts, and individualized, sport-specific outcome measures, rather than a one-size-fits-all approach to studying cycle effects across all sports and athletes [s1]. To that end, the review includes a suggested standardized protocol intended to help future studies actually be comparable to each other — addressing what has apparently been a real problem in this research area, where inconsistent methodology across studies makes results hard to pool or generalize [s1].

What this means for how the topic gets discussed

Cycle-tracking has become a visible part of some elite women's sports programs, often marketed or discussed as though the performance effects of cycle phase are well established. This review is a useful corrective to that framing without dismissing the underlying question: the best hormone-confirmed evidence available right now does not show a statistically significant effect on VO2 max specifically, but the sample size behind that finding is small enough that it doesn't rule out real, if modest or individually variable, effects either. The honest state of the science, per this review, is "not yet well studied enough to know for certain" rather than "no effect exists."

Sources

• The effects of hormone changes over the menstrual cycle on elite athlete performance: meta-analysis and suggested standardised protocol — Reproduction and Fertility, 2026-07-15