How long children sleep every night can affect their behavioural patterns and lead to changes in eating habits, a new study suggests.

The study, which was conducted by researchers at the University of Auckland, found that the less time a child slept, the more likely theywere tohave behavioural problems.

Children who slept for less than nine hours were also more likely to become overweight or obese,according to thestudy.

"Short sleep duration was associated with a three-fold increased risk of the child being overweight or obese," said Ed Mitchell, the study's author, in a release. "Attention to sleep in childhood may be an important strategy to reduce the obesity epidemic."

The study examined the sleep patterns of 591 children using actigraphy — a method ofcharting movement in sleep without the use of invasive tools.

The children were assessed at birth, at one year, at 3½ and at seven.

The researchers in New Zealanddetermined that the children spent on average 10.1 hours in bed per night. This differed at different times of the week, in different seasons and in cases where the kids had brothers or sisters.

The researchers state that the recommended amount of sleep for children in pre-school is 11-13 hours a night and 10-11 hours for children who are school age.

The study is published in the Jan. 1 issue of the Journal Sleep.