A systematic review of the relationship of physical activity and health status in adolescents.

Background: Reduced physical activity is a known risk factor for many illnesses. Research in adolescent populations found increased physical activity levels improves objective health outcomes, but there is conflicting evidence regarding the relationship between physical activity levels and self-reported health status. To synthesise current evidence on the association between physical activity and self-reported health status in adolescents. Secondary objectives are to assess whether the relationship is dose dependant, and the appropriateness of WHO recommendations on adolescents' physical activity. The main databases were searched using keywords for the main outcome of interest (health status, health behaviour and self-perception) and exposure of interest (motor activity, physical activity and exercise), supplemented with manual searches, secondary citation and reference searches. Quality appraisal was carried out using the Strengthening the Reporting of Observational Studies in Epidemiology checklist. Eleven studies entered this review. Nine studies reported a significant relationship between increased levels of physical activity and improved self-reported health status, however two did not. Two studies followed up participants and found that the relationship persisted over time. Two papers described a dose-response relationship. Improvements in self-perceived health can be observed even below the current recommended levels of physical activity. The review supports initiatives to encourage adolescents to engage in physical activity as it improves self-reported health status. Sub-optimal levels of physical activity can also be beneficial. Further research should use standardised measurement scales and objectively measured physical activity levels. The roles of gender, income and culture should be further investigated.