Effect of zinc and selenium supplementation on serum testosterone and plasma lactate in cyclist after an exhaustive exercise bout.

Zinc and selenium are essential minerals and have roles for more than 300 metabolic reactions in the body. The purpose of this study was to investigate how exhaustive exercise affects testosterone levels and plasma lactate in cyclists who were supplemented with oral zinc and selenium for 4 weeks. For this reason, 32 male road cyclists were selected equally to four groups: PL group, placebo; Zn group, zinc supplement (30 mg/day); Se group, selenium supplement (200 μg/day); and Zn-Se group, zinc-selenium supplement. After treatment, free, total testosterone, and lactate levels of subjects were determined before and after exhaustive exercise. Resting total, free testosterone, and lactate levels did not differ significantly between groups, and were increased by exercise (P > 0.05). Serum total testosterone levels in Zn group were higher than in Se group after exercise (P < 0.05). Serum-free testosterone levels in the Zn group were higher than the other groups (P < 0.05).There was an insignificant difference between levels of lactate in the four groups after exercise (P > 0.05). The results showed that 4-week simultaneous and separately zinc and selenium supplementation had no significant effect on resting testosterone and lactate levels of subjects who consume a zinc and selenium sufficient diet. It might be possible that the effect of zinc supplementation on free testosterone depends on exercise.

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