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.
A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. ABSTRACT Background: The effect of intensity and duration of physical activity (PA) on weight loss has been well described. However, the effect of the frequency of weekly PA on weight loss is still unknown. Objective: The purpose of this study was to evaluate the effect of the frequency of weekly PA sessions while maintaining the same total activity time on weight loss during a 24-wk weight loss program. Design: Overweight and obese women [n = 75; body mass index (BMI; in kg/m 2 ): 27-37; age: 18-40 y] who had a normally sedentary lifestyle were randomly allocated to 1 of 2 intervention groups: a high-frequency physical activity (HF) or a low-frequency physical activity (LF) group. The HF group included 50 min/d PA, 6 d/wk (300 min/wk). The LF group included 100 min/d PA, 3 d/wk (300 min/wk). Both groups were advised to follow the same dietary weight loss program. Results: Both groups showed a significant decrease in anthropometric measurements and significant improvements in cardiometabolic disease risk characteristics over the 24 wk of the study. Compared with the HF group, the LF group had a greater decrease in weight (mean 6 SD; LF: 9.58 6 3.77 kg; HF: 7.78 6 2.68 kg; P = 0.028), BMI (LF: 3.62 6 1.56; HF: 2.97 6 1.02; P = 0.029) and waist circumference (LF: 9.36 6 4.02 cm; HF: 7.86 6 2.41 cm; P = 0.031). However, there were no significant differences in carbohydrate metabolism characteristics or lipid profile after the 24 wk of intervention. Conclusion: Weekly PA undertaken over fewer sessions of longer duration during the week could be more effective for weight loss than when undertaken as more frequent shorter sessions in overweight and obese women on a weight loss program. This may be helpful for those who are neither willing nor able to schedule time for PA almost every day to achieve weight loss. This trial was registered at www.irct.ir as IRCT201402157754N4.Am J Clin Nutr
Improved physical fitness in preconception period results in significant changes in bone gene expressions of female offspring, in particular towards osteogenic responses with improved RANKL/OPG ratio.
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