The Impact of Physical Activities on Men's Mental Health: A Focus on Bipolar Disorder Prevention.

Bipolar disorder (BD) is a prevalent psychiatric condition characterized by extreme mood fluctuations between manic and depressive episodes, significantly affecting social and occupational functioning. The etiology of BD is multifactorial, involving genetic, environmental, and lifestyle factors. While previous research has focused on the genetic and environmental contributors to BD, the role of physical activity as a modifiable lifestyle factor remains underexplored. This study investigates the causal relationship between different types of physical activity, particularly heavy do-it-yourself (DIY) activities, and BD using Mendelian randomization (MR). The study employs MR to examine the causal link between physical activity and BD. Genetic variants associated with various forms of physical activity were selected from large-scale genome-wide association studies. The study uses several MR techniques, including inverse variance weighting (IVW), MR-Egger, and weighted median methods, to analyze the relationship between physical activity (e.g., heavy DIY, light DIY, vigorous exercise, and walking) and BD. Instrumental variables were chosen based on their strong association with physical activity and their independence from other potential confounders. The MR analysis revealed a significant causal relationship between heavy DIY activities and reduced BD risk (OR = 0.333; 95% CI [0.111, 0.997]; p = .049). In contrast, no significant causal associations were found for the other types of physical activity examined. The IVW method indicated significant heterogeneity, prompting the use of a random-effects model, which confirmed that the results were not biased by heterogeneity or pleiotropy. Sensitivity analyses, including MR-Egger and MR-PRESSO, showed no significant pleiotropy, reinforcing the reliability of the findings. Leave-One-Out analysis and funnel plots further supported the robustness of the causal estimate. This study provides compelling evidence for the protective role of heavy DIY activities in reducing the risk of BD, suggesting that high-intensity physical activities may have a beneficial impact on mood regulation and the prevention of BD. The findings highlight the importance of considering gender differences in physical activity interventions for BD prevention and management. Future research should explore the neurobiological mechanisms underlying this association and further investigate the effectiveness of different types of physical activities in BD prevention and treatment strategies.