Top female athletes have often found that prime physical performance comes at the price of interruptions not only in their regular menstruation cycles but also in their fertility. Many find it difficult if not impossible to get pregnant while maintaining their demanding training regime.
Research by the Norwegian University of Science and Technology (NTNU) reinforces the fact that the female body suffers from reduced fertility under heavy physical training. It concludes that the body may simply not have the energy to handle both the demands of an athlete and of getting pregnant.
Based on results from the Health Survey of Nord-Trøndelag from the mid 1980s and a follow-up survey in the mid 1990s, the study looked at healthy women of childbearing age with no history of fertility problems.
Sigridur Lara Gudmundsdottir, a PhD researcher with the NTNU’s Human Movement Science Programme, sounds a reassuring note however in that “…the vast majority of women in the study had children in the end. And those who trained the hardest in the middle of the 1980s were actually among those who had the most children in the 1990s.” So thankfully even though heavy exercise can interfere significantly with fertility, it’s almost always short-lived.
It is speculated that high levels of physical activity require so much energy that at times it leaves the body with an energy deficiency that then prevents certain essential hormonal mechanisms from taking place thus inhibiting fertilisation.
In the study, two particular groups were particular at risk for infertility: those who trained virtually every day and those who trained to the point of exhaustion. Age was also an important factor as women under 30 years of age showed increased infertility due to heavy and/or daily training. Gudmundsdottir adds that “when we compared those who trained to exhaustion to those who trained more moderately, we found that the first group had a three-fold greater risk of impaired fertility.”
This is not however a call for giving up all physical activity, since women who engage in moderate physical activity have improved insulin function and hormonal profile leading to improved conditions for fertility.
“We believe it is likely that physical activity at a very high or very low level has a negative effect on fertility, while moderate activity is beneficial,” says Gudmundsdottir.
Since identifying the right amount of exercise depends on each person’s metabolism, she recommends that women pay close attention to their menstrual cycles as “… a long cycle or no menstruation at all is a danger signal.”