Cardiorespiratory Fitness in Young Adulthood and Depressive Symptoms Later in Life Among Swedish Men

Objectives This study investigated whether cardiorespiratory fitness (CRF) in young adulthood is associated with depressive symptoms several decades later and if later-life physical activity and self-rated health mediate this association. Methods The sample comprised 690 Swedish men completing a CRF test at age 18 and self-reported depressive symptoms around age 61. Unadjusted and adjusted logistic and linear regression models and Bayesian mediation analyses were estimated. Results Medium and high CRF at age 18, compared with low CRF, were associated with lower odds of clinically significant depressive symptoms in late adulthood. The odds ratios of clinically significant depressive symptoms were 0.329 (95% CI [0.157, 0.687]) for men with medium and 0.383 (95% CI [0.157, 0.939]) for men with high CRF compared with those with low CRF. No credible mediated associations were observed. Conclusion These findings suggest that promoting fitness early in life may represent a useful preventive strategy for mental health resilience across the life course.