Prospective study of hormonal and semen profiles in marathon runners.

OBJECTIVE

To investigate the effect of marathon training on hormonal and semen profiles in male athletes.

DESIGN

Prospective longitudinal study over 1 year.

SETTING

Department of Obstetrics and Gynaecology, University of Cape Town, South Africa.

PARTICIPANTS

Twenty-four healthy male marathon runners, 25 to 54 years of age.

MAIN OUTCOME MEASURES

Hormonal evaluation included determination of plasma concentrations of total T, LH, FSH, PRL, E2, and P. Semen analyses included an evaluation of count, motility, morphology, and volume. These profiles were correlated with training intensity.

RESULTS

The intensity of training increased significantly in the first 5 months of the study. This was accompanied by a significant rise in serum PRL levels and a fall in P levels. No other significant hormonal changes were identified. The semen volume and sperm motility and morphology fell significantly during training, but there was no significant alteration in the sperm count.

CONCLUSION

This longitudinal study demonstrates that endurance training can modify significantly hormonal profiles and semen parameters in long-distance runners.