Associations between physical activity and mental health and behaviour in early adolescence

We examined associations between objectively-measured physical activity, depressive-symptoms, and emotional and behavioural difficulties in adolescents from a UK cohort. Data from 4755 participants (45% male) from the Avon Longitudinal Study of Parents and Children (ALSPAC) with physical activity assessed by accelerometry at age 11 was analysed. Indication of depressive symptoms (Short Moods and Feelings questionnaire) were obtained from parental reports at age 11 and self-reports at age 13. Behavioural and emotional problems were assessed by parents and teachers at age 11 and 13 using the Strengths and Difficulties Questionnaire (SDQ). At age 11, males averaged 29 minutes (SD = 17) of daily moderate-to-vigorous physical activity (MVPA) compared with 18 minutes (SD = 12) among females. Higher MVPA at age 11 was associated with decreased depressive-symptoms in females at age 11 after adjusting for confounders. Among males, a positive change in MVPA between the ages of 11 and 13 was associated with a reduction in depressive symptoms. Negative associations were also found between MVPA at age 11 and the emotional symptoms scale of the SDQ at age 11 and age 13 in females. Higher MVPA predicted a decreased score on the hyperactivity subscale of the SDQ at 11 and 13 for both sexes. All effect sizes were small. Higher MVPA was associated with reduced depressive symptoms, behavioural and emotional-difficulties in early adolescence, however the magnitude of effects was small. Efforts to support MVPA in this age group are therefore warranted.