Does the Menstrual Cycle Affect Olympian Performances?

Holy Hormones Honey!  Well, obviously not for Michael Phelps and the other male Olympians. I am heartened by this comment by de Jonge : ‘It’s perfectly possible that, with further research, future female athletes may be able to take advantage of their female hormone changes to improve their Olympic performance.’  I believe this to be true not only for athletes but for all women.

However, I am curious at the long-term reproductive health effects of women athletes who are ignoring the cyclical nature of the hormone cycle – especially over years of intense training in preparation for the highly-competitive sport.

Blood, sweat and tears: the menstrual cycle and the Olympics

The Conversation
Providing independent analysis and commentary from academics and researchers.

By Xanne Janse de Jonge

1 August 2012, 6.19am AEST

For some female athletes, “counting the days” to their Olympic event may have a double meaning. These Olympians may be worried about “what time of the month” it is going to be when they are expected to deliver their best sporting performance ever.

Most female athletes will be exposed to changes in their female hormone levels throughout the Olympics. The two main ones, oestrogen and progesterone, will fluctuate as a result of the menstrual cycle or oral contraceptive use. These hormone changes have many effects outside of the reproductive system and may influence exercise performance.

Even though this may not be the case for all athletes, as high training load is often linked with menstrual irregularities, these hormone fluctuations may affect the performance of female Olympians.

Of course performance at the Olympics will be influenced by many other factors, but we’ll focus here on the effects of female hormones on exercise performance, in particular on muscle strength, aerobic performance and endurance performance.

Research with large hormone changes, such as during menopause and hormone replacement therapy, has shown that oestrogen has a strengthening effect on muscle. Female athletes may be stronger during the oestrogen peak of the menstrual cycle, which occurs around nine-to-13 days after the onset of bleeding.

Some older research findings have supported this suggestion, but unfortunately they did not actually measure oestrogen levels. Therefore it is unclear if the higher strength happened at the same time as the high oestrogen.

Our research did measure hormone levels and we showed no changes in muscle strength and fatigue over the menstrual cycle.

Only a few studies have investigated the effect of oral contraceptives on muscle strength and they also suggest there’s no change in strength during an oral contraceptive cycle. So it seems that the female athletes participating in strength specific sports may not need to worry about their female hormones as they count down towards their Olympic event.


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Author: Leslie Carol Botha

Author, publisher, radio talk show host and internationally recognized expert on women's hormone cycles. Social/political activist on Gardasil the HPV vaccine for adolescent girls. Co-author of "Understanding Your Mood, Mind and Hormone Cycle." Honorary advisory board member for the Foundation for the Study of Cycles and member of the Society for Menstrual Cycle Research.