Physical and mental load of tactical athletes during Arctic military training

Introduction – Tactical athletes require consistent physical and mental exertion to succeed in their mission, often under life-threatening conditions. Soldiers as tactical athletes are exposed to a myriad of stressors that may deteriorate performance, especially in harsh military environments. It remains unclear which combination of traits, habits, and characteristics of soldiers affects the likelihood of performance decrement during military operations. Methods – This observational cohort study investigated the differences between a physical-load group and a mental-load group of cadets (n = 49) during a 2-week near-Arctic winter training. One group comprised first-year cadets who had physical demands, while the second-year cadets had more leadership requirements (command and control) and fewer physical demands. The chance occurrence of a viral infection in the first-year cadets provided a naturalistic experiment to study vulnerability to the illness. Demographics, trait resilience, exercise training behavior, and sleep habits were assessed prior to training. Throughout training, wrist-worn accelerometers monitored sleep-wake activity, and cadets completed daily self-report entries on perceived sleepiness, stress, and mood states. Body composition was measured before and after training. Results – Findings showed the following: (1) poorer self-reported mood, stress, and sleepiness during preparation and cleanup phases than during simulated combat among the mental-load group, but for the physical-load group, these measures were poorest during the simulated combat; (2) an overall decrease in fat mass after the training; and (3) survival analysis demonstrated that older age and less frequent endurance training habits significantly predicted the likelihood of illness during training. Discussion – Leaders of tactical athletes should be aware of the taxing mental load not just for the main event itself, but for preparation and cleanup phases. Military experience and aerobic fitness might attenuate the likelihood of succumbing to viral illnesses during missions involving close quarters.