REPRODUCTIVE FUNCTION IN MALE ENDURANCE ATHLETES - SPERM ANALYSIS ANDHORMONAL PROFILE

The purpose of this investigation was to study the effects of enduranc e exercise on male reproductive function (sex hormones and seminograms ). Professional cyclists [n = 12; mean age 24 +/- 2 (SD) yr], elite tr iathletes (n = 9; 26 +/- 3 yr), recreational marathon runners (n = 10; 32 +/- 6 yr), and sedentary subjects (control group; n = 9; 30 +/- 4 yr) were selected as subjects. For each group, the following parameter s were measured three times during the sports season (training period: winter; competition period: spring; resting period: fall): percentage of body fat, hormonal profile (resting levels of follicle-stimulating hormone, luteinizing hormone, total and free testosterone, and cortis ol), and seminograms (quantitative parameters: sperm volume and sperm count; qualitative parameters: sperm motility and morphology). The fol lowing comparisons were made in the measured parameters: 1) within gro ups (longitudinal design) and 2) between groups in each of the three p eriods (cross-sectional design) and over time (mixed design). In addit ion, both the volume and the intensity of training of each subject dur ing the season (except for the control group) were quantified. Despite significant differences in training characteristics and in body fat p ercent, in general no significant differences (P > 0.05) were found in hormonal profiles or in semen characteristics between or within group s. A lower sperm motility (46.2 +/- 19.5%), however, was observed in t he cyclists during the competition period when compared either with th e other groups during this same period (P < 0.05) or with themselves d uring the other two periods of study (P < 0.01). In any case, the late r phenomenon was attributed to physical factors associated with cyclin g, such as mechanical trauma to the testis and/or increased gonadal te mperature. In conclusion, our findings suggest that endurance exercise does not adversely affect the hypothalamic-pituitary-testis axis.