Why Do We Sleep?
No one knows for certain why we sleep, but we all need it. Some researchers think that sleep provides essential rest for both the body and the mind. During sleep, the body recovers from the previous day’s activities. Some of the cells that have worn out are replaced. The rest we get during sleep enables us to be alert and active the next day.
Inside part of the brain are “wake-up” centers, which keep us alert all day. At night, these centers are somehow turned off.
Scientists aren’t exactly sure what kinds of organizing our brain does while we sleep, but they think that sleep might be the time when the brain sorts and stores information, replaces chemicals, and solves problems. Eventually, it becomes impossible for the brain to give its directions to the rest of the body without sleep — the brain needs to spend time in bed and catch its ZZZs!
The amount of sleep a person needs depends a lot on his or her age. Babies sleep a lot — about 14 to 15 hours a day! But many older people only need about 7 or 8 hours of sleep each night. Most kids between the ages of 5 and 12 years old require 10 to 11 hours of sleep. Some kids might need more and some need less. We will probably spend about one third of our lifetime sleeping.