What happens when you sleep?

Outwardly, your eyelids are closed, your muscles are relaxed, and you are usually lying down. Your heartbeat and breathing rate slow down. Slowly you become less aware of what may be happening all around. For example, George is asleep and can't hear the announcement for his flight!

The amount of sleep needed by humans is variable. As you grow older, you need less sleep. A newborn baby spends more time asleep than awake. Most adults need about eight hours of sleep a day.

No one knows why you sleep. Some scientists think that sleep restores energy to the body, particularly to the brain and nervous system.

     "People deprived of sleep lose energy and become quick-tempered. After two days without sleep, a person finds that lengthy concentration becomes difficult. Through pure determination, a person may perform tasks well for short periods but is easily distracted. Many mistakes are made, especially in routine tasks, and attention slips at times. Every "sleepless" person experiences periods of dozing off for a few seconds or more. The person falls completely asleep unless kept active continuously.

     People who go without sleep for more than three days have great difficulty thinking, seeing, and hearing clearly. Some have periods of hallucinations, during which they see things that do not really exist. They also confuse daydreams with real life and often lose track of their thoughts in the middle of a sentence.

     Human beings have gone without sleep for up to 11 days. But people who have stayed awake so long lose contact with reality for periods of time. They become suspicious and fearful of others. For example, they may believe that a doctor is an undertaker who has come to bury them, or that their food has been poisoned."

Excerpted from The World Book Multimedia Encyclopedia

"George Files" by Parenting the Next Generation