Abstract
BACKGROUND: Cognitive and mental health problems are highly prevalent in adolescence. While higher levels of physical fitness may mitigate these problems, there is a lack of long-term follow-up studies on the associations of physical fitness from childhood with cognition and mental health in adolescence. OBJECTIVE: We investigated the associations of physical fitness from childhood to adolescence over an 8-year follow-up with cognition and mental health in adolescence. METHODS: The participants were 241 adolescents (112 girls), who were 6-9 years at baseline and 15-17 years at 8-year follow-up. Average and change scores for cardiorespiratory fitness (maximal power output [W(max)]; peak oxygen uptake [VO(2peak)]), motor fitness (10 × 5-m shuttle run), and muscular fitness (standing long jump; hand grip strength) were calculated. Global cognition score was computed from six individual cognitive tasks, and perceived stress and depressive symptoms were assessed at the 8-year follow-up. The data were analysed using linear regression models adjusted for age, sex, and parental education. RESULTS: Average motor fitness was positively associated with global cognition score (standardised regression coefficient [β] - 0.164, 95% confidence interval [CI] - 0.318 to - 0.010) and inversely with perceived stress (β = 0.182, 95% CI 0.032-0.333) and depressive symptoms (β = 0.181, 95% CI 0.028-0.333). Average cardiorespiratory fitness was inversely associated with perceived stress (W(max): β = - 0.166, 95% CI - 0.296 to - 0.036; VO(2peak): β = - 0.149, 95% CI - 0.295 to - 0.002) and depressive symptoms (W(max): β = - 0.276, 95% CI - 0.405 to - 0.147; VO(2peak): β = - 0.247, 95% CI - 0.393 to - 0.102). A larger increase in cardiorespiratory fitness was associated with lower perceived stress (W(max): β = - 0.158, 95% CI - 0.312 to - 0.003; VO(2peak): β = - 0.220, 95% CI - 0.395 to - 0.044) and depressive symptoms (W(max): β = - 0.216, 95% CI - 0.371 to - 0.061; VO(2peak): β = - 0.257, 95% CI - 0.433 to - 0.080). CONCLUSIONS: Higher levels of motor fitness in childhood and adolescence were associated with better cognition in adolescence. Higher levels of and larger increases in cardiorespiratory fitness from childhood to adolescence were associated with better mental health in adolescence.