Effects of High-Intensity Interval Training on Steroid Hormones and Psychological Outcomes in Healthy Male Adolescents: A Randomized Controlled Trial

The study investigated the effects of high-intensity interval training (HIIT) on cardiorespiratory fitness, hormonal, and psychological markers in adolescents. Twenty-eight healthy male adolescents were randomized to a HIIT group or a non-training control group. HIIT comprises three sessions per week for 10 weeks, alternating 30 s runs at high-intensity and low-intensity. VO2max was estimated using the incremental running test. Plasma testosterone and cortisol were assessed by ELISA methods. Depression, anxiety, and stress scores were determined using the Depression Anxiety Stress Scales-21. Data were analyzed using two-way ANOVA with repeated measures. Significant “group × time” interactions were detected for VO2max, testosterone, cortisol, testosterone-to-cortisol ratio, and stress score, but not for anxiety and depression scores. HIIT resulted in increased VO2max (p < 0.001, d = 1.04), testosterone (p = 0.005, d = 0.52), and testosterone-to-cortisol ratio (p = 0.008, d = 1.05), and decreased cortisol (p = 0.036, d = 1.09) and stress score (p = 0.020, d = 0.98). Ten-week HIIT resulted in an improvement in physical fitness, steroid hormonal balance, and self-reported stress symptoms, but no changes in depressive and anxiety symptoms in comparison to the control group. The findings should be interpreted with caution due to limitations, including the small sample size and the lack of assessment of sex-related differences. Further research is required to elucidate the topic.