Physical Activity Predicts Better Lung Function in Children and Adolescents.

PURPOSE To investigate (1) whether physical activity is associated with lung function in children and adolescents, (2) whether this association is modified by the subjects' weight status, and (3) whether this association is mediated by the body mass index. METHODS This is a cross-sectional study including 460 participants aged 7-17 years, randomly selected from 13 public schools in southern Brazil. Collected data included anthropometric measures, physical activity, screen time, and spirometric measures expressed as percent predicted values. Data were analyzed using multiple linear regression and 2-way analysis of variance. RESULTS There were positive associations between physical activity and forced vital capacity (β = 3.897, P = .001) and forced expiratory volume in the first second (β = 2.931, P = .021). The effect modification by weight status was not statistically significant (forced vital capacity: Pinteraction = .296 and forced expiratory volume in the first second: Pinteraction = .057). Body mass index did not mediate the association between physical activity and spirometric outcomes (P > .05). CONCLUSION Regular physical activity was associated with higher forced vital capacity and forced expiratory volume in the first second in children and adolescents. The observed associations were not modified by weight status nor mediated by body mass index. Our results reinforce the importance of regular physical activity for the development of lung function during childhood and adolescence.