Menstrual cycles appear to have little or no negative impact on women's athletic performance, says the December issue of the Penn State Sports Medicine Newsletter. Despite the physiological ups and downs of the menstrual cycle, female athletes have developed ways to compensate for any disadvantages.
World records have been set during all phases of the menstrual cycle, the newsletter says.
Hormones, whether produced naturally or taken in a synthetic form, can potentially affect athletic performance, but measuring this influence is difficult because interactions of those hormones are complex, always changing and individual in nature. However, VO2max is not the only or necessarily the best predictor of performance. Both of these hormone concentrations vary quite a bit during the cycle. According to Lebrun, some evidence indicates that, even though women feel bloated during the week or so before their periods, their energy metabolism still might be relatively good. In fact, adverse effects on athletic ability due to hormones are least noticeable during the menstrual period and immediately afterward.