The influence of physical and mental fatigue on physical effort-based decisions: a systematic review

Fatigue has increasingly been investigated as a factor influencing physical effort-based decisions, yet no systematic review has synthesized whether and how physical and mental fatigue affect such choices. The objectives of this review were to investigate the direct effects of physical and mental fatigue, as well as their effects together with other factors, on physical effort decisions. Following PRISMA guidelines, a search was conducted in PubMed, Scopus, Web of Science, CENTRAL, and EBSCOhost up to May 12, 2026. Studies were included if they tested healthy adults, experimentally induced physical or mental fatigue, and assessed decision-making outcomes involving physical effort. Ten experiments from nine articles met the inclusion criteria. Overall, neither physical nor mental fatigue showed consistent direct effects on physical effort choices. However, physical fatigue emerged as a moderating factor, strengthening the influence of subjective effort costs on the likelihood of selecting less demanding options. Mental fatigue, in contrast, appeared to influence decisions through a mediating mechanism, increasing perceived effort and altering benefit–cost evaluations. Thus, although operating via distinct processes, both physical and mental fatigue may influence physical effort-based decisions. Future research should clarify the mechanisms and inform interventions aimed at mitigating fatigue and promoting physical activity in adults.