Should exercise be adapted to a woman’s menstrual cycle?

Many female athletes believe that their performance is affected by their menstrual cycle. Cecilia Fridén, associate professor at the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, is going to find out whether that is true.

Portrait of Celilia Fridén wearing a striped shirt.
In recent years, Cecilia Fridén has noticed a growing interest in women's exercising, and in the impact of the menstrual cycle. Photo: Alexander Donka.

Text: Ann Kjellqvist, first published in Swedish in the magazine Medicinsk Vetenskap no 2/2021. 

What do we know about how the female menstrual cycle affects women when they exercise? 

“The studies carried out so far have been quite small with many methodological weaknesses and the results are not consistent. Thus, at the present time, it is difficult to give any general advice on whether women should adapt their exercising based on their menstrual cycle.  

Tell us about the study in question. 

"The Swedish Olympic Committee , SOK, is currently putting substantial resources into women's sport. Together with Professor Angelica Lindén Hirschberg, I will be leading a study on the periodisation of exercise, which we expect will start this coming autumn. We will investigate whether the varying hormonal levels present during the menstrual cycle can be utilised to optimise the effect of exercise.”  

“For example, is it beneficial to do intensive training during the first two weeks and then exercise more sparingly for the next two weeks? In order to test this, the athletes in the study will exercise according to different training arrangements, while a control group will exercise as usual, that is, evenly during their menstrual cycle period. The study will include both cardio and strength training.”  

Is syncing the exercising to the menstrual cycle relevant for all women? 

"We have been researching the impact of the menstrual cycle on physical performance for the last twenty years and have previously looked at regular exercisers.” The current study is being done on "elite athletes" because it is difficult to get elite athletes to change their training schedule to follow a study design. Depending on what the study shows, the results may be relevant for not only elite female athletes but also regular exercisers. However, the way in which a woman experiences and is affected by her menstrual cycle is incredibly individual, and this must be taken into account when advising on how women can adapt their training.  

Can the birth-control pills affect exercise? 

"The use of birth-control pills among elite female athletes has increased in recent years, but there is not much research on birth-control pills and exercise. Therefore, we will also use a survey study to investigate what proportion of elite women athletes use birth-control pills, and whether they feel that these affect their physical performance.”  

What do you hope the study can add? 

"There is a widespread perception among athletes and sports clubs that female athletes benefit from periodising their training based on their menstrual cycle. However, up to now there is not enough research to support this view. We hope that our study will help in increasing knowledge in order to provide evidence-based advice with support in research on how elite female athletes can plan their training in order to optimise results and performance.” 

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