Gender peculiarities of cortisol, testosterone and vitamin D blood levels in athletes

   Objective. To assess the gender characteristics of the concentration of cortisol, testosterone and vitamin D in blood serum in athletes, and to analyze the correlations between vitamin D levels and the hormonal status of athletes.   Materials and methods. 52 athletes (32 men and 20 women) were examined, their age was 17-23, their sports specialization was cyclic sports (kayaking) and acyclic sports (gymnastics, martial arts), and qualification – candidates for master of sports, masters of sports. Venous blood was taken in the morning on an empty stomach before training loads. Determination of total testosterone and cortisol concentration and assessment of vitamin D level by determination of its metabolite 25(OH)D (25-hydroxyvitamin D) in blood serum was performed by immunochemiluminescent method.   Results. In male athletes with vitamin D deficiency, serum testosterone concentration and anabolic index were significantly lower (p = 0.0093 and p = 0.0015, respectively) compared to the same indices in the group of athletes with normal vitamin D content. Correlation analysis in male athletes revealed a positive correlation between serum 25(OH)D (25-hydroxyvitamin D) content and testosterone concentration (r = 0.36; p < 0.05), as well as between 25(OH)D content and anabolic index (r = 0.42; p < 0.05). The group of female athletes with vitamin D deficiency showed significantly lower serum testosterone concentration compared to athletes with normal vitamin D levels (p = 0.0112). No significant relationships were found between vitamin D levels and cortisol concentrations in both male and female athlete groups.    Conclusion. The study results can be the evidence of modulation effect of vitamin D on testosterone levels in male athletes, indicating the importance of controlling and correcting vitamin D content in the dynamics of the training process.