All participants take part in an aerobic exercise training program with a total weekly energy expenditure of 17.5 kcal/kg/week over the entire 12-week intervention period. The dose of exercise is determined using exercise prescription guidelines established by the American College of Sports Medicine (ACSM, American College of Sports Medicine, 2000). All trainings take place at a local public gym under supervision of previously trained exercise coaches from the Institute of Exercise and Health Sciences of the University Basel. Participants can choose between different training devices for cardiovascular training. Energy expenditure is assessed using the values of burned calories provided by the training devices based on age, weight and training performance. Heart rate is monitored during all training sessions with chest belt heart rate monitors (Polar®) to ensure training below the anaerobic threshold with heart rates between 60 - 75 % of the maximum heart rate.

burnout severity measured by psychopathology, cortisol secretion, BDNF, sleep, cognitive performance, and psychological functioning