Daily physical activity, human development index and insomnia in a representative sample of Brazilian adolescents: a cross-sectional analysis.

ABSTRACT BACKGROUND: Although there is a growing body of research pointing towards the need to investigate how different movement behaviors, such as physical activity and sleep, influence each other, the joint relationship between these factors and insomnia has been little explored among adolescents in developing countries. OBJECTIVES: To investigate the association between daily physical activity and insomnia in a national sample of Brazilian adolescents, according to the Human Development Index (HDI) of each Brazilian region. DESIGN AND SETTINGS: Cross-sectional study on 102,072 Brazilian students aged 11 to 19 years, selected from all regions of the country. METHODS: Information on insomnia and physical activity was self-reported by adolescents. RESULTS: Our analyses revealed that girls who accumulated at least 60 minutes/day of physical activity on up to three days/week were less prone to present insomnia. This pattern of association was maintained only for those who lived in high HDI regions (odds ratio, 0.87; 95% confidence interval, 0.75-0.99). For boys, there was a positive association between the number of active days and protection against insomnia, especially for those who lived in high HDI regions. CONCLUSION: Even amounts of physical activity that were lower than the weekly guidelines, were associated with better sleep quality for Brazilian adolescents, especially girls, and even for those who lived in regions with greater social and economic vulnerability.