Children's Sleep Duration Differs According To The Time Of Day, Week, And Year, And Can Influence Their Weight And Behavior
01 January 2008
The duration of a child's sleep can vary, depending on the time of day, week and year. Further, children who don't get enough nightly sleep are more likely to be overweight and have behavioral problems.
The study, authored by Professor Ed Mitchell, of the University of Auckland in New Zealand, focused on 591 seven-year-old children whose sleep duration was assessed by actigraphy (a non-invasive method used to study sleep-wake patterns and circadian rhythms by assessing movement) at four different stages of their young lives: at birth, at one year, at three-and-a-half years and at seven years.
According to the results, the average time spent in bed was 10.1 hours. Sleep duration was shorter:
- On weekends than on weekdays.
- In the summer, compared with spring, autumn and winter.
- In those with no younger siblings.
- When bedtime was after 9:00 p.m.
Children who slept less than nine hours were more likely to be overweight or obese and to have a 3.34 percent increase in body fat than those who slept for more than nine hours. Short sleep duration was also associated with higher emotional liability scores.
"Sleep is important for health and well-being throughout life," said Professor Mitchell. "Few studies have objectively measured sleep duration. In this large study of sleep in seven-year-olds, there was considerable variation in duration of sleep. Sleep duration was 40 minutes longer in winter than summer and was 31 minutes longer on weekdays than on the weekend. Short sleep duration was associated with a three-fold increased risk of the child being overweight or obese. This effect was independent of physical activity or television watching. Attention to sleep in childhood may be an important strategy to reduce the obesity epidemic."
It is recommended that children in pre-school sleep between 11-13 hours a night and school-aged children between 10-11 hours of sleep a night.
