Close to 90 percent of children have at least one sleep-related problem, such as night terrors, teeth-grinding or bed-wetting. At least 30 percent of children younger than six have difficulties sleeping six consecutive hours.

Researchers have found sleepless children can become overweight and hyperactive. 26 percent of children that sleep fewer than 10 hours a night between two and half years and six years are overweight. The figure drops to 15 percent of those that sleep 10 hours, and falls to 10 percent among those that sleep 11 hours.

The relationship between sleep and weight could be explained by a change in the secretion of hormones that's brought on by lack of sleep.