There are days when your legs feel heavier and the exercise session seems to last longer. Many women find that this is related to certain times in their menstrual cycle, and this has given rise to the myth that there is a direct correlation between physical performance and fluctuations in the sex hormones throughout the cycle. However, a new study by Associate Professor Mette Hansen and PhD Tine Dam from the Department of Public Health at Aarhus University, suggests that the drop in performance does not directly correlate with fluctuations in sex hormones. 

In the study, young untrained women were had their physical performance tested 7-9 times throughout their menstrual cycle. The study found that there was a 2-6% drop in power performance during jumping and cycling sprint tests at the start and end of their cycle. But more surprising was the fact that the decline in performance was not directly linked to fluctuations in the sex hormones, says Associate Professor Mette Hansen:

“We could see that the fluctuations in performance did not correlate with fluctuations in the sex hormones. Instead, the fluctuations in the performance were consistent with how well the women felt before the physical test, how motivated they were, and their own expectations towards their performance on the day – and for these parameters, women generally experienced a drop in the early bleeding phase.”

Menstrual cycle apps may be unnecessary

In pursuit of the optimal training session, the world of sports has developed many different tools for organising training programmes, including menstrual cycle apps that many female atheltes use when planning their physical training.

“There is a certain amount of hype about the correlation between fluctuations in sex hormones and performance in the world of sports. Our results suggest that not all female atheltes need to spend unnecessary time tracking their cycle for performance purposes, because fluctuations in the sex hormones do not seem to have a direct influence on performance,” she says.

While sex hormones do not play a role in reduced performance, the study instead shows that the women’s own sense of their performance capacity on the day plays a role. Perhaps unsurprisingly, low motivation and low expectations resulted in worse performance in the test. The fact that this coincided in the experiment with menstrual bleeding (just before and during the start of the period) is consistent with the discomfort that some women often feel in the days leading up to and during their period.

“It’s obvious that if you feel tired, unmotivated or have physical discomfort in connection with your menstrual cycle, this may affect your efforts in connection with a training session, and thus your performance. What our study shows is that the degree of self-perceived physical and mental well-being is lowest just before and during the bleeding phase, and that it is the mental state that to a greater extent predicts physical performance, rather than measurable fluctuations in the sex hormones per se,” says Mette Hansen.

Following up with new study

The study is the first of its kind in which womens physical performance has been measured 7-9 times during the menstrual cycle, and where their performance has been directly compared with variations in sex hormones and the women’s own reports on their physical and psychological comfort, motivation and expected performance capacity before the test.

Associate Professor Mette Hansen and Postdoc Mette Bisgaard have now just begun recruiting candidates for a new international project in which 200 well-trained female atheltes from ten test places in the world will participate, and this time the study will be expanded.

“In addition to testing well-trained female atheltes instead of untrained women, we will control the dietary intake and physical exercise of the female athetles the day before each testing day. In this way, we can reduce the risk of our results being affected by diet and exercise. In addition, we will also study the influence of use of oral contraceptives,” she says.

You can read more about the upcoming project here: Menstrual cycle, contraceptive pills and performance (au.dk)

Facts:

• 40 women aged 18-35, who were not physically trained, participated in the study.
• The women’s physical performance was tested 7-9 times during their menstrual cycle.
• The women participated in physical tests in which they were asked to jump and cycle.
• In addition, the women completed a questionnaire in which they stated their level of motivation and their own expectations towards their performance.

About the published study:

• Prospective cohort study with 30 young, untrained women with a regular menstrual cycle who did not use contraceptive pills, and ten contraceptive pill users
• Partners: Tine Vrist Dam1, Line Barner Dalgaard1, Vassilis Sevdalis1, Bo Martin Bibby2, Xanne Janse De Jonge3, Claus H. Gravholt4,5, and Mette Hansen1
  Section of Sport Science, Department of Public Health, Aarhus University, Aarhus, Denmark
  Section of Biostatistics, Department of Public Health, Aarhus University, Aarhus, Denmark
  Faculty of Science, University of Newcastle, Ourimbah, Australia
  Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
  Department of Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark
• External funding: Team Denmark, the Aarhus University Research Foundation and the Toyota Foundation

Read more: https://journals.lww.com/acsm-msse/Fulltext/2022/10000/Muscle_Performance_during_the_Menstrual_Cycle.7.aspx 

Contact

Associate Professor Mette Hansen  
Aarhus University, Department of Public Health – Sport Science
E-mail: mhan@ph.au.dk
Direct line: +45 5166 6551
Mobile: +45 5166 655