Objective: This study measured the cortisol levels of professional athletes during a CrossFit® championship. Then, it evaluated the physiological response caused by cortisol. Increased cortisol levels may interfere with the athletes’ performance and muscle recovery. Materials and Methods: A prospective observational cross-sectional study was performed with a sample of eight female professional athletes, aged between 20 and 34 years, enrolled in the 2017 Brazil CrossFit Championship (TCB), held in Valinhos, state of Sao Paulo, Brazil. The salivary samples were obtained during the three days of the championship in two different moments: in the morning, before athletes’ warm-up, and 15 minutes after the last workout of each day. Results: Before warming up, the mean values of salivary cortisol were 15.9 ng/mL, 13.2 ng/mL, and 13.1 ng/mL, respectively. After the last workout, the mean values for cortisol were 6.4 ng/mL, 9.6 ng/mL, and 7.1 ng/mL, respectively. A statistically significant difference was found on the first day of competition. The results presented the expected diurnal cycle of this hormone. Conclusion: CrossFit® is a sport that alternates medium- to high-intensity exercises, including gymnastics, metabolic conditioning, and weight lifting. This competitive sport presents a variability of stressors, which may increase cortisol production and secretion according to different studies. This study found that the physiological stress of a CrossFit® championship affects the production of cortisol and increases the stimulation of the hypothalamic axis. However, the normal cortisol secretion response suggests a physiological adaptation or alteration in the cortisol receptor in the athletes studied. Further studies carried out with a larger sample are necessary to assess these neuroendocrine changes.
Keywords: CrossFit®. Cortisol. Physical activity. Women.