Exercise is advised to stay healthy, reduce stress and lose weight. WHO recommends adults 150 minutes of moderate activity per week. But intense exercise, by acting on sexual hormones, could have an impact on fertility and libido: thus, very sporty women may notice a disruption of their menstrual cycles or even amenorrhoea. So, in men, what is the effect of intense sport on fertility and libido?
In their study published in Medicine and Science in Sports and Exercise, researchers from the University of North Carolina recruited 1,077 men who answered questions about their physical activity and sexual life. Most participants were running or cycling.
The sport advised for fertility but not high dose
The results show that those who trained most (the longest and the most intensely) had a reduced libido. Conversely, men who had mild to moderate physical activity had higher levels of libido. One hypothesis to explain these effects is that intense sport induces physical fatigue and lower testosterone levels.
The authors conclude that when a couple consults for infertility, the question of exercise should be asked. Indeed, intense physical activity can reduce the number of sperm in semen, if the organism is regularly at high temperature, because heat is harmful to spermatozoa. A 2011 study showed reduced sperm concentration in men with more than five hours of cycling per week. However, in general, sport, rather than physical inactivity, is rather beneficial to fertility: a study in 2016 taught that sport improves sperm quality. Moderate and regular exercise was the most beneficial.