Gentle aerobic exercise takes hours off period pain

Primary dysmenorrhoea, period pain that occurs without an underlying pelvic condition, is one of the most common complaints among adolescents and young women, costing school days, work days and quality of life. Aerobic exercise had previously been reported to help, but a vague sense that exercise helps is not much use in practice: the type of exercise, its intensity, how long each session should last and how often to do it were all unclear. This review set out to size the effect of aerobic exercise on period pain properly and to look for dose-response patterns across different types and schedules of exercise.

The authors searched ten databases, including Web of Science, the Cochrane Library, PubMed and CINAHL, for randomised controlled trials of aerobic exercise lasting at least one menstrual cycle in non-athlete women with primary dysmenorrhoea, with pain intensity or pain duration as outcomes. Sixteen studies qualified, 15 of them involving adolescents, totalling 918 participants aged 15 to 43 with an average age of 21.26. Study quality was assessed with the Cochrane risk of bias tool, results were pooled with random-effects models, and pre-specified subgroups based on exercise type, intensity, session length, weekly frequency and programme length were analysed.

Aerobic exercise reduced pain intensity with a large pooled effect and shortened pain duration by an average of 12.53 hours compared with comparator conditions. Both headline results came with a caution: the trials disagreed considerably on how big the benefit was, so the averages hide a wide spread. The subgroup analyses were the most practically interesting part. Pilates showed the largest effect on pain intensity, and low-intensity exercise, a frequency of two or fewer sessions per week, and programmes running for two menstrual cycles were also associated with the biggest effects. The authors rated the evidence behind these subgroup patterns as moderate quality.

The direction of the finding is not new, as the authors note aerobic exercise had already been reported to alleviate primary dysmenorrhoea; the contribution here is the attempt at dose-response detail. The pattern it found is counterintuitive, with gentler and less frequent exercise showing the largest effects, which cuts against the assumption that more effort buys more relief, though subgroup findings drawn from disagreeing trials should be held loosely. The review also leaves clear gaps: the authors call for future randomised trials in younger age groups specifically, so that treatment strategies can be personalised for adolescents rather than extrapolated.

For anyone who experiences period pain, this is evidence that movement is a credible non-drug option with a measurable average effect, shortening pain as well as dulling it. Notably, the strongest signals came from low-intensity formats such as Pilates done a couple of times a week rather than from hard training, so intensity does not appear to be the price of relief. The trials disagreed on the size of the benefit and this analysis cannot say what will work for any one person, but it is a reason to view gentle, regular aerobic exercise as more than folk advice for dysmenorrhoea.