It turns out the less time a child sleeps, the more emotional he is and the more likely he is to become overweight, even when controlling for TV watching and exercise.
In a study of more than 500 seven-year-olds, researchers used a monitor to determine how long the children slept. The study published in the January 2008 issue of Journal Sleep, showed those who got less than nine hours were three times more likely to become overweight or obese than those who slept for more than nine hours.
While the short sleepers were also more emotional, the good news is that it didn’t seem to affect their IQ or hyperactivity scores. The study’s authors recommend seven-year-olds get at least nine hours’ sleep. “Children who need to be woken for school aren’t getting sufficient sleep,” notes study co-author and professor Ed Mitchell.