Mental fatigue impairs physical performance in humans

tigue is a psychobiological state caused by prolonged periods of demanding cognitive activity. Although the impact of mental fatigue on cognitive and skilled performance is well known, its effect on physical performance has not been thoroughly investigated. In this randomized crossover study, 16 subjects cycled to exhaustion at 80% of their peak power output after 90 min of a demanding cognitive task (mental fatigue) or 90 min of watching emotionally neutral documen-taries (control). After experimental treatment, a mood questionnaire revealed a state of mental fatigue (P 0.005) that significantly reduced time to exhaustion (640 316 s) compared with the control condition (754 339 s) (P 0.003). This negative effect was not mediated by cardiorespiratory and musculoenergetic factors as phys-iological responses to intense exercise remained largely unaffected. Self-reported success and intrinsic motivation related to the physical task were also unaffected by prior cognitive activity. However, men