FERTILITY NOT AFFECTED BY HARD EXERCISE
Report #7203
A report from Finland shows that endurance training has no harmful effects on pregnancy or delivery (1).
When some women exercise a lot, they stop menstruating and when some men exercise most of the time, they are too tired to make love, but there is little evidence that hard exercise reduces a person's ability to have children. Some women develop irregular periods when they exercise, but most had irregular periods before they started to exercise. The most common cause of irregular periods in women who exercise is not exercise, it's not eating enough food.
Sperm counts and the hormones associated with fertility remain normal in marathon runners training on more than 100 miles a week. However, some men who competed in 7 day running races did have slightly reduced sperm counts and hormone levels, but they were in an event that was so demanding that it depleted their bodies of everything, and their sperm counts and hormone levels returned to normal soon after the race. Some athletes take anabolic steroids illegally to make themselves stronger. This suppresses fertility, but it does not keep them from making love. Four months after the athletes stop taking anabolic steroids, their sperm counts and hormone levels returned to normal.
So, when you are trying to start a family, you can stop exercising if you want, but there is no evidence that it will increase your chances of having a baby.
By Gabe Mirkin, M.D., for CBS Radio News
1) J Penttinen, R Erkkola. Pregnancy in endurance athletes. Scandinavian Journal of
Medicine & Science in Sports. 7: 4 (AUG 1997):226-228. 2) Steroids: Fertility and Sterility. 1989(December);52(6):1041-7. 3) Sperm Counts: Fertility and Sterility 1990(April);53(4):688-92.
Reported 9/1/97; Checked 9/5/05