The effect of exhaustion exercise on thyroid hormones and testosterone levels of elite athletes receiving oral zinc

Neuro Endocrinol Lett. Feb-Apr 2006;27(1-2):247-52.

Abstract

Objectives: The present study aims to investigate how exhaustion exercise affects thyroid hormones and testosterone levels in elite athletes who are supplemented with oral zinc sulfate for 4 weeks.

Methods: The study included 10 male wrestlers, who had been licensed wrestlers for at least 6 years. Mean age of the wrestlers who volunteered in the study was 18.70 +/- 2.4 years. All subjects were supplemented with oral zinc sulfate (3 mg/kg/day) for 4 weeks in addition to their normal diet. Thyroid hormone and testosterone levels of all subjects were determined as resting and exhaustion before and after zinc supplementation.

Results: Resting TT3, TT4, FT3, FT4 and TSH levels of subjects were higher than the parameters measured after exhaustion exercise before zinc supplementation (p<0.05). Both resting and exhaustion TT3, TT4 and FT3 values after 4-week zinc supplementation were found significantly higher than both of the parameters (resting and exhaustion) measured before zinc supplementation (p<0.05). Resting total testosterone and free testosterone levels before zinc supplementation were significantly higher than exhaustion levels before zinc supplementation (p<0.05). Both resting and exhaustion total and free testosterone levels following 4-week zinc supplementation were found significantly higher than the levels (both resting and exhaustion) measured before zinc supplementation (p<0.05).

Conclusion: Findings of our study demonstrate that exhaustion exercise led to a significant inhibition of both thyroid hormones and testosterone concentrations, but that 4-week zinc supplementation prevented this inhibition in wrestlers. In conclusion, physiological doses of zinc administration may benefit performance.

MeSH terms

  • Adolescent
  • Adult
  • Exercise / physiology*
  • Exercise Test
  • Humans
  • Testosterone / blood*
  • Thyroid Hormones / blood*
  • Thyrotropin / blood
  • Thyroxine / blood
  • Triiodothyronine / blood
  • Wrestling / physiology
  • Zinc / pharmacology*

Substances

  • Thyroid Hormones
  • Triiodothyronine
  • Testosterone
  • Thyrotropin
  • Zinc
  • Thyroxine