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Fertil Steril. 1993 Oct;60(4):686-92.

Overtraining affects male reproductive status.

Author information

1
Department of Human Biodynamics, University of California, Berkeley 94720.

Abstract

OBJECTIVE:

To substantiate the hypothesis that strenuous exercise disrupts the hypothalamic-pituitary-gonadal axis in men.

DESIGN:

Longitudinal study.

SETTING:

Normal human volunteers in an academic research environment.

PATIENTS:

Five endurance-trained men (maximum oxygen consumption 65.4 +/- 3.6 mL/kg per minute [means +/- SEM]) with normal spermatogenic and hormonal profiles.

INTERVENTIONS:

Semen and blood samples were collected bimonthly before, immediately after, and 3 months after overtraining, which was defined as twice the previous average weekly training volume with unchanged intensity.

MAIN OUTCOME MEASURE:

Testosterone, cortisol, and sperm concentration.

RESULTS:

Basal T levels decreased to 5.37 +/- 67 ng/mL from 8.68 +/- 93 ng/mL (conversion factor to SI unit, 3.47) immediately after overtraining and basal cortisol levels increased to 215.3 +/- 31 ng/mL from 145.7 +/- 27 ng/mL (conversion factor to SI unit, 2.76). This inverse relationship was highly correlated (r = -0.92). Both cortisol and T levels returned to pretraining values 3 months after resumption of previous training volume. Sperm count (91 +/- 23.3 x 10(6)) decreased significantly by 43% immediately after overtraining (52 +/- 6.8 x 10(6)) and by 52% 3 months after overtraining (44.5 +/- 20 x 10(6)). However, all values remained within normal range and would not be expected to affect fertility.

CONCLUSIONS:

Our results indicate that overtraining reduces T levels, which is highly correlated with an increase in levels of cortisol and possibly a subsequent decrease in sperm concentration 74 days later.

PMID:
8405526
[Indexed for MEDLINE]

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