Washington , Jan 1 (ANI): A new study has shed light on childrens sleep patterns, by finding that a childs sleep duration can differ, depending on the time of day, week and year, and that insufficient sleep can cause obesity and behavioural problems in kids.

The study was led by Professor Ed Mitchell, of the University of Auckland in New Zealand .

For the study, the researchers observed 591 seven-year-old children whose sleep duration was evaluated 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.

The results revealed that the average sleeping time for a kid was 10.1 hours.

The researchers also found that the sleep duration was shorter on weekends than on weekdays; in summer than in spring, autumn and winter; in kids without younger siblings; and in kids who go to bed after 9:00 p.m.

According to the findings, the kids who slept for 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.

The researchers also associated short sleep duration with higher emotional liability scores.

“Sleep is important for health and well-being throughout life. 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, said Professor Mitchell.

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, he added.

This study is published in the recent issue of Sleep. (ANI)