Ways of unraveling how and why physical activity influences mental health through statistical mediation analyses

ObjectiveKnowledge of the mechanisms responsible for the effects of physical activity on aspects of mental health is limited. Appropriate experimental trials and statistical mediation analyses of experimental, quasi-experimental and observational studies can help shed light on these mechanisms. A critical overview of methods for mediation analyses is provided. Recommendations relevant to studies in the field of physical activity and mental health are made.StrategyMain issues pertaining to the identification of mechanisms of influence (mediators) are discussed. Recommendations on appropriate methods of mediation analysis for cross-sectional and longitudinal data and ways of presenting findings from such analyses are provided. Finally, future directions in methods of mediation analyses are briefly outlined.ConclusionsThere is a dearth of mediation studies in the field of physical activity and mental health, which explains why not much is known about the underlying mechanisms of influence. An array of experimental and statistical methods is available to those who wish to unravel how and why physical activity affects various aspects of mental health in diverse populations and circumstances. The correct use of, and presentation of findings from, methods of mediation analyses is vital for clarifying how mental health can be enhanced through participation in physical activity.