engleski

The associations of sleep duration and physical activity in 11-12 year old children

Aim: This multi-centre study aimed to explore the associations between sleep and physical activity in 11-12 year old children. Methods: The sample comprised 233 children (111 boys), mean age (SD) = 11.4 (0.4) years from several elementary schools in Zagreb (Croatia), Ljubljana (Slovenia) and Ann Arbor (Michigan, United States). Physical activity and time spent sleeping were assessed during four consecutive days (including 2 school days and 2 weekend days) using a multiple sensor body monitor (SenseWear Pro3 Armband, BodyMedia, Pittsburgh, USA). Sleep duration was averaged according to the formula: (average school day*5+average weekend day*2) / 7. After that, children were grouped according to sleep duration in normal sleep (>7 hours on average) or short sleep group (<7 hours on average). Physical activity was divided into 3 intensity categories: light activity (1.5-3 METs), moderate activity (3-6 METs) and vigorous activity (>6 METs). Differences in physical activity duration between normal and short sleepers were assessed using analysis of covariance controlling for age and country. In addition, to further assess the association of sleep duration and activity, partial correlation coefficients controlling for age, gender and country were calculated. Results: No significant differences were noted for any of the physical activity measures in boys, girls or both gender combined. Similarly, after controlling for age, gender and country, sleep duration was not related to physical activity duration. However, a weak inverse relationship with energy expended during physical activity was found (r=-0.13, p=0.05). Conclusion: Results of this study do not support the hypothesis that short sleep is linked to decreased physical activity level in this group of children.

sleep quality; youth;

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