Monaz: Hello, I'm Monaz Mehta, editor in the Cochrane Editorial and Methods department. Dysmenorrhoea is the medical name given to painful uterine cramps of menstrual origin, which is also known as period pain. There are several Cochrane Reviews of ways that might ease this and the one investigating the benefits of exercise was updated in September 2019. Here’s one of the authors, Jane Chalmers from Western Sydney University in Australia, to tell us what it found.

Jane: Dysmenorrhoea, or period pain, is a huge problem worldwide, with over two thirds of women under the age of 25 reporting it. This has impacts on quality of life, causing absence from school and work and reduced participation in sport and social activities. Most women attempt to manage the pain with over-the-counter medications such as ibuprofen and paracetamol, or self-care strategies such as rest and the application of heat, but all of them  with little success. Physical activity has long been advocated as an alternative and we did this review to get a better understanding of the conflicting evidence on its effectiveness, and have found that it is probably worth trying.
We identified 12 randomised trials, involving nearly 900 women. The studies were mostly from Iran and India, with four and three studies respectively; but also included research in Egypt, Korea, New Zealand and the USA. A range of types of exercise have been tested, with four studies comparing high intensity exercise to no exercise, six comparing low intensity exercise to no exercise, and one comparing low intensity exercise to non-steroidal anti-inflammatories, or NSAIDs. Forms of exercise included treadmill training, Zumba, yoga, stretching, and core strengthening. The frequency of exercise varied from once to six times per week, with sessions lasting between 10 and 60 minutes. 
When we combined the results of the higher-quality studies in a meta-analysis, this showed that both low- and high-intensity exercise seem to have large effects on the severity of menstrual pain compared to no exercise, although the effect on overall menstrual symptoms and quality of life is much less clear. There is also a lot of uncertainty around the comparison of exercise with NSAIDs, so we don’t know whether exercise reduces menstrual pain, use of rescue analgesic medication, or absence from work or school more or less than these drugs do. 
In summary, we’ve shown that there is some low-quality evidence to suggest that exercise, performed for 45-60 minutes at least three times per week, may provide a clinically significant reduction in menstrual pain intensity. Given this finding, as well the overall health benefits of regular exercise and the relatively low risk of adverse events reported in the general population, it seems reasonable for women to consider using exercise to manage their menstrual pain. In the future, we need more research of higher quality to determine the optimal type, timing, and dosage of exercise to maximise these reductions in pain.

Monaz: To find out more about the types of exercise that have been tested in the randomized trials to date, and to watch for future updates of this review if the new studies become available, go online to Cochrane Library dot com and search 'exercise for period pain' to find the full review.