SYDNEY – Many women Olympic athletes go on contraceptive pills over worries that their period will fall on the day of a critical event and blight their chances of winning a medal.

For all but distance runners in the second half of their menstrual cycle competing on a hot day, their worries are misplaced, an Australian researcher said Thursday.

“There’ve been gold medals won and world records set at each stage of the menstrual cycle, so it’s not as if there’s clear evidence there saying you can’t win a medal when you’re having your period,” Newcastle University’s Xanne Janse de Jonge said.

And it could be that further research into hormonal changes will allow athletes to harness the menstrual cycle to actually improve performance because early work shows that they may be stronger nine to 13 days after the start of bleeding.

“The easiest way to split it up is the first two weeks and the second two weeks,” de Jonge said. “The second two weeks of the monthly cycle are when the temperature is higher, and that’s definitely where temperature regulation is a problem.” (more…)