Healthier Minds in Fitter Bodies: A Systematic Review and Meta-Analysis of the Association between Physical Fitness and Mental Health in Youth.

Background: Physical fitness is an important marker of current and future health status, yet the association between physical fitness and indicators of mental health in youth has not been systematically reviewed and meta-analyzed.
Objective: The aim of this work was to systematically review and meta-analyze the association between physical fitness components (i.e. cardiorespiratory fitness, muscular fitness, speed-agility, flexibility and fitness composite) and mental health indicators (i.e. psychological well-being and psychological ill-being) in preschoolers, children and adolescents.
Design: Systematic review and meta-analysis.
Data Sources: Systematic searches were conducted in PubMed, Web of Science and Scopus from database inception to May 2020.
Eligibility Criteria: Studies (cross-sectional, longitudinal and intervention designs) were included if they measured at least one physical fitness component and one mental health indicator in healthy youth (2-18 years).
Results: A total of 58 unique studies (52 cross-sectional, 4 longitudinal and 4 intervention studies) met all eligibility criteria and were included. There was a significant positive overall association between physical fitness and mental health in children and adolescents (pooled r = 0.206, p < 0.001). We found suggestive evidence of moderation by age group, fitness components and socioeconomic status (all p < 0.08). No relevant studies focusing on preschoolers were identified. Evidence based on longitudinal and intervention studies was limited.
Conclusion: We observed a small to medium sized positive association between physical fitness and overall mental health in youth. However, as the majority of studies were cross-sectional, additional longitudinal and intervention studies are needed to provide evidence of causation.
Trial Registration: PROSPERO registration number CRD42017080005.
(© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)