Prolonged or severe stress has been found to inhibit the hypothalamic-pituitary-gonadal axis (HPG) and its testosterone release. In contrast, acute stress, including competition, social evaluation, or physical challenges, shows more inconsistent response patterns. This study examined changes in cortisol and testosterone across different types and durations of stress in the same individuals. We further explored the influence of baseline levels on hormonal stress responses. Sixty-seven male officer cadets in the Swiss Armed Forces (mean age 20.46 years ± 1.33) were assessed during two different acute stressors-the Trier Social Stress Test for Groups (TSST-G) and a brief military field exercise-and in the long-term during the 15-week officer training school. Several saliva samples were collected before and after the acute stressors for cortisol and testosterone. Morning testosterone was assessed four times during officer training school. There were significant increases in cortisol and testosterone during the TSST-G and the field exercise. Baseline levels of testosterone were negatively associated with acute cortisol response during the field exercise but not during the TSST-G. Morning saliva testosterone decreased during the first 12 weeks of officer training school and increased again in week 15, with no differences to baseline levels. The findings suggest that group stress tests such as the TSST-G or field exercises in groups may be particularly challenging for young men. The results also point to an adaptive role of testosterone during acute challenges during prolonged stress.
Keywords: Cortisol; TSST-G; military field exercise; officer training school; stress; testosterone.