Sleep is as important and necessary to the human body as water and food. Lack of sleep has negative effects on health. The duration of sleep depends on a person's physical condition and activities. Children from 0 to 3 months sleep for 14 to 17 hours; children 6-13 are 9-11; 14 to 17 year olds get 8 to 10 hours of sleep and adults 26 to 64 get 7 to 9 hours of sleep. As a person ages, the inside of the brain also ages and sleep is affected.