Exploring the Link Between Sleep Timing, Diet, and Physical Activity in Children

The Importance of Sleep for Health

Researchers have investigated the relationship between sleep timing and both diet and physical activity levels in children aged 9 to 11 years. It is widely recognized that sufficient sleep is crucial for overall health. Previous research indicates a connection between inadequate sleep and issues such as excess body weight and poor dietary habits among children. Despite efforts to increase sleep duration in this age group, the effects on body weight, diet, and activity levels have been minimal. Consequently, experts suggest that sleep timing—encompassing bedtimes and wake times—may serve as a significant predictor of weight, diet, and activity levels in children, irrespective of total sleep hours.

Study Overview

A team of researchers in New Zealand aimed to determine the association between sleep timing and diet as well as physical activity levels among schoolchildren. Their findings were recently published in the Journal of Sleep Research. The study involved 439 children aged 9 to 11 years from 17 schools in Dunedin, New Zealand. On a designated school day, researchers measured the children’s body weight and height, and they completed questionnaires regarding their dietary habits and physical activity. Parents were also asked to fill out similar questionnaires to validate the children’s responses. To monitor sleep patterns and physical activity, each child wore a wrist accelerometer around the clock for eight days, except during bathing or swimming.

Classification of Sleep Timing Groups

After data analysis, researchers categorized the children into four distinct sleep timing groups: early sleep/early wake, early sleep/late wake, late sleep/early wake, and late sleep/late wake. The results showed no significant difference in sleep duration between the early sleep/early wake (8.6 hours) and late sleep/late wake groups (8.5 hours). However, the early sleep/late wake group averaged about 9.2 hours of sleep, while the late sleep/early wake group averaged 8.0 hours.

Healthier Patterns Linked to Earlier Sleep Cycles

Though the study revealed no significant differences in average body weight among the four groups, there was a tendency for a higher percentage of overweight or obese children to belong to the late sleeping groups. The research also compared dietary patterns and the frequency of consuming specific food groups, alongside the amount of moderate to vigorous physical activity across the sleep timing categories. Findings indicated that children in the late sleep/late wake group had a notably lower frequency of fruit and vegetable consumption, coupled with a higher intake of sweetened beverages compared to those in the early sleep/early wake group. Furthermore, children in the late sleep/late wake category engaged in significantly fewer minutes of moderate to vigorous physical activity daily than their counterparts in the early sleep/early wake group.

Conclusions and Future Research Directions

Overall, children who followed an early sleep/early wake schedule exhibited healthier eating habits and engaged in more physical activity than those in other sleep timing groups. These results suggest that sleep timing, independent of sleep duration, correlates with children’s dietary choices and activity levels. However, the study does not establish causation for the observed differences. Ongoing research is necessary to uncover the underlying mechanisms linking sleep timing to health outcomes, which will aid in developing effective strategies to promote healthy sleep behaviors among children.

Reference

Harrex H, Skeaff S, Black K, et al. Sleep timing is associated with diet and physical activity levels in 9-11 year old children from Dunedin, New Zealand: the PEDALS Study. J Sleep Research (2017). Accepted 4 Oct 2017. DOI: 10.1111/jsr.12634