Mediating Mechanisms Linking Exercise and Mental Health: A Sports-Science Perspective with Implications for Athlete Performance

Abstract

Although exercise consistently improves mental health, sports scientists and coaches need evidence about how exercise produces those benefits and how those mechanisms translate into athletic performance and training practice. We conducted a PRISMA-guided systematic review of studies that formally tested mediators in the exercise → mental-health pathway to identify mechanisms most relevant to sport performance and coaching. Electronic searches (PubMed, Scopus, Web of Science, PsycINFO, SPORTDiscus; inception-March 2025) identified 30 mediation studies (cross-sectional, longitudinal, RCTs) that together sampled adolescents, athletes, older adults and clinical groups. We extracted study characteristics, indirect effect estimates or required statistics for conversion, risk-of-bias ratings, and sport-relevant moderators (sport vs non-sport samples; competitive level; modality). Across studies, psychosocial mediators (self-efficacy, body-esteem, mastery) and affective responses (increases in positive affect, reductions in negative affect) were the most robust pathways. Behavioural mediators (sleep quality, fatigue reduction) and physiological mediators (fitness, functional capacity, BDNF in clinical samples) contributed especially in physically demanding or rehabilitative contexts. Importantly, when studies involved sport participants or sport-structured training, mediators linked more directly to performance outcomes (motivation, training adherence, competitive anxiety). We present subgroup analyses and sensitivity checks (excluding cross-sectional designs) that strengthen causal interpretation and propose a mechanism-driven framework for coaches: (1) design mastery-based progressions to boost self-efficacy, (2) structure sessions to maximise positive affect and recovery, and (3) monitor sleep and fatigue as mediators of both mental health and performance. These sport-focused mechanistic insights support targeted training prescriptions that maximise athlete well-being and performance.