Physical Activity and Sleep Quality in Spanish Primary School Children: Mediation of Sex and Maturational Stage

Background: sleep is a physiological process that is critical for physical and mental health in children. Childhood encompasses diverse developmental stages that may affect the impact of physical activity on sleep quality, which may also be influenced by sex. The purpose of this study was to examine the mediation effect of sex and, as well as maturational stage on the association between physical activity and sleep quality, among primary school children. Methods: this was a cross-sectional study of 954 Spanish primary school students (437 early childhood and 517 middle childhood) with a mean age of 10.5 ± 1.2 years. Participants reported their sleep quality using the Pittsburgh Sleep Quality Index and their physical activity levels using the Physical Activity Questionnaire. Results: our study found that physical activity is associated with improved sleep quality in children, particularly during middle childhood. Higher physical activity was linked to better sleep quality and reduced sleep latency (p = 0.044). Sleep quality was generally better in males than in females (p = 0.002) and was also better in early than middle childhood (p = 0.000). Conclusions: especially in middle childhood, physical activity promotes children’s sleep quality. Thus, educational institutions should promote or improve the implementation of physical activity in the school context in order to benefit children’s sleep quality and, hence, improve their quality of life and wellbeing.