Abstract
There is strong evidence to support the association between daily physical activity and sleep parameters in children and adolescents. Physical activity and outdoor play are favourably associated with most sleep outcomes in school children. The aim is to find out the levels of physical activity and the quality of sleep in Basque schoolchildren aged between six and seventeen and to analyse the possible differences between those who carry out some kind of physical sports activity and those who do not. The sample consisted of 1082 schoolchildren (50.1% male and 49.9% female). Differences between groups were compared using the Mann-Whitney U test (2 samples) and Kruskal-Wallis one-factor ANOVA (k samples). A total of 723 (66.94%) of the participants said they practiced some physical sports activity. The accelerometers obtained significant differences in all levels of physical activity, as well as in sleep efficiency, with higher levels of physical activity (sedentary p = 0.001; light p = 0.017; moderate p = 0.009; vigorous p = 0.001 and moderate-to-vigorous physical activity p = 0.002) and better sleep efficiency (p = 0.002) in those schoolchildren who perform some type of physical sports activity. A significant difference in time spent in sedentary activities was also observed between primary and secondary school pupils of both sexes and regardless of the degree of physical sports activity completion.