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Effect of fatiguing bicycle exercise on thyroid hormone and testosterone levels in sedentary males supplemented with oral zinc.

Kilic M.
Clinical Trial 2007; 28(5): 681-685 PubMed PMID: 17984944 Citation  Keywords:  Administration, Oral, Adolescent, Adult, Dietary Supplements, Exercise:physiology, Exercise Test, Fatigue:blood, Humans, Male, Physical Exertion:physiology, Testosterone:blood, Thyroid Hormones:blood, Thyroxine:blood, Trace Elements:administration & dosag.   

OBJECTIVE: The aim of this study was to determine how exercise affects thyroid hormones and testosterone levels in sedentary men receiving oral zinc for 4 weeks.

METHODS: The study included 10 volunteers (mean age, 19.47+/-1.7 years) who did not exercise. All subjects received supplements of oral zinc sulfate (3 mg/kg/day) for 4 weeks and their normal diets. The thyroid hormone and testosterone levels of all subjects were determined at rest and after bicycle exercise before and after zinc supplementation.

RESULTS: TT3, TT4, FT3, and total and free testosterone levels decreased after exercise compared to resting levels before supplementation (p<0.01). Both the resting and fatigue hormone values were higher after 4 weeks of supplementation than the resting and fatigue values before supplementation (p<0.05).

CONCLUSION: The results indicate that exercise decreases thyroid hormones and testosterone in sedentary men; however, zinc supplementation prevents this decrease. Administration of a physiologic dose of zinc can be beneficial to performance....

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

Kilic M, Baltaci A, Gunay M, Gökbel H, Okudan N, Cicioglu I.
Journal Article 2006; 27(1-2): 247-252 PubMed PMID: 16648789 Citation  Keywords:  Adolescent, Adult, Exercise:physiology, Exercise Test, Humans, Testosterone:blood, Thyroid Hormones:blood, Thyrotropin:blood, Thyroxine:blood, Triiodothyronine:blood, Wrestling:physiology, Zinc:pharmacology,.   

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....

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