The purpose of study was to investigate the effect of a high-intensity interval training (HIIT) intervention on cardiorespiratory fitness (CRF), hormonal, and mental health markers in male adolescents. The main question it aims to answer is: Does HIIT improve CRF, hormonal (testosterone and cortisol levels, testosterone:cortisol ratio), and mental health (depression, anxiety and stress scores) markers. Researchers will compare HIIT (designed to experimental group) to non-training intervention (designed to control group) to see if the training program works to improve the health status. HIIT consisted of three sessions per week for 10 weeks, comprising of three sets of four to eight bouts of 30-s runs at high intensity \[100-110% of maximal aerobic speed (MAS)\], interspersed with 30-s recovery runs at low intensity (50% of MAS) between bouts.