The role of volume and intensity on the association between physical activity and mental health among adolescents: a cross-sectional study

Objective: To analyze the association between volume and intensity of physical activity and mental health among adolescents.Methods: Cross-sectional study with 604 Brazilian adolescents. Data were assessed using a self-report questionnaire. The outcomes were suicidal ideation, suspicion of common mental disorders, and negative self-perception of mental health. The independent variables were leisure physical activity at low and moderate-to-vigorous intensities. Volume was analyzed in two ways: any volume (presence vs absence), and volume classified according to amount in minutes of weekly physical activity: inactive (0), low active (1-419), and high active (>= 420). Poisson regression was performed to estimate prevalence ratios.Results: Any volume of moderate-to-vigorous physical activity was significantly associated with a lower prevalence ratio of all outcomes (PR 0.67 to 0.77). Compared to inactive adolescents, those who were classified as low active for moderate-to-vigorous intensity, presented a lower likelihood of having suicidal ideation, suspicion of common mental disorders, and negative self-perception of mental health (PR 0.70 to 0.76). Furthermore, high active adolescents in moderate-to-vigorous physical activity presented lower suicidal ideation and negative self-perception of mental health (PR 0.62 and 0.57).Conclusions: The promotion of moderate-to-vigorous intensity physical activity at any volume can benefit the mental health of adolescents, however, no association was evidenced for low intensity physical activity.