Gender Differences in Chronic Hormonal and Immunological Responses to CrossFit^®

This study was designed to analyze the chronical responses of the hormonal and immune systems after a CrossFit^® training period of six months as well as to compare these results between genders. Twenty-nine CrossFit^® practitioners (35.3 ± 10.4 years, 175.0 ± 9.2 cm, 79.5 ± 16.4 kg) with a minimum CrossFit^® experience of six months were recruited, and hormonal and immune responses were verified every two months during training. The training was conducted in five consecutive days during the week, followed by two resting days. Testosterone (T) values were significantly higher at the last measurement time (T6 = 346.0 ± 299.7 pg·mL^-1) than at all the other times (p < 0.002) and were higher in men than in women (p < 0.001). Cortisol (C) levels were lower at all times compared to the initial level before training, and differences were observed between men and women, with men having a lower value (T0: p = 0.028; T2: p = 0.013; T4: p = 0.002; and T6: p = 0.002). The TC ratio in women was lower at all times (p < 0.0001) than in men. Significant effects on CD8 levels at different times (F_(3.81) = 7.287; p = 0.002; η² = 0.213) and between genders (F_(1.27) = 4.282; p = 0.048; η² = 0.137), and no differences in CD4 levels were observed. CrossFit^® training changed the serum and basal levels of testosterone and cortisol in men (with an increase in testosterone and a decrease in cortisol).