Running: Overtraining & Hormones

Let's dig a little deeper into the effects of overtraining.

Testosterone levels will decline. A team of researchers grouped 286 subjects into moderate or heavy exercise groups. They ran for 2 hours, 5 days per week for about 1 year. After that, they spent 9 months with a low intensity running schedule. They found that the pituitary hormones LH and FSH (luteinizing hormone, follicle stimulating hormone) decreased, testosterone levels decreased, and sex hormone binding globulin levels increased. Levels improved back to normal during the low intensity recovery period. They concluded,

"Long-term strenuous treadmill exercises (overtraining syndrome) have a deleterious effect on reproduction." Journal of Endocrinology 2009 Mar;200(3):259-71. Epub 2008 Dec 9

Females can also experience reproductive dysfunction. While the mechanisms are still to be determined, the probable suspect is decreased estrogen production as a result of overtraining. This does more than set women up for poor athletic performance. It sets you up for osteoporosis, infertility, decreased muscle mass & behavioral problems. Journal of Endocrinological Investigation 2001 Nov;24(10):823-32.

The hormone cost of overtraining is considerable. The consequences of these shifts are significant.