Sleep problems may lead to obesity

Children tend to vary widely in their sleep habits, but those who are regularly sleep-deprived may have a higher risk of becoming overweight. In general, experts recommend that school-age children get 10–11 hours of sleep per night, while preschoolers should get 11–13 hours. Past studies have hinted that insufficient sleep can encourage weight gain. Though the reasons are not clear, one theory is that sleep deprivation alters hormones involved in appetite control and metabolism. Researchers from New Zealand and Australia studied 591 children aged seven years. They measured sleep duration by actigraphy, along with height, weight, BMI, percentage body fat, intelligence and behaviour (based on questionnaires given to parents and teachers). On an average, the seven-year-olds got 10 hours of sleep. But it was found that, in general, children tended to sleep a little less on weekends than on weekdays, and during the summer compared with other seasons. Those who were particularly "short sleepers" at the age of seven years were at greater risk of being overweight or having behavioural problems. Also, children who slept less than nine hours per night were three times as likely as longer sleepers to be overweight or obese. Similarly, short sleepers were more likely to have behavioural issues and symptoms of attention-deficit / hyperactivity disorder. The findings suggest that inadequate sleep may contribute to both weight and behavioural problems in young children. The link between sleep deprivation and weight remained when the researchers accounted for the children's exercise habits and TV watching — two key factors in children's risk of becoming overweight. This suggests that there is a definite effect of sleep deprivation on weight. This underscores the importance of children getting the recommended amount of sleep, as it is in part a modifiable risk factor for other poor health outcomes in childhood, including obesity.