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How Sleep Works

By Alexia O.
New York, Age 12

How Sleep Works
Sleep is one of those funny things about being a human being — you just have to do it. Have you ever wondered why? And those crazy dreams, like the one where a bad person is chasing you and you can't run or yell. Does that make any sense?

If you have ever wondered about why people have to sleep or what causes dreams, then read on. In this article, you'll find out all about sleep and what it does for you.
Characteristics of Sleep
We all know how sleep looks — when we see someone sleeping, we recognize the following characteristics:
If possible, the person will lie down to go to sleep.
The person's eyes are closed.
The person doesn't hear anything unless it is a loud noise.
The person breathes in a slow, rhythmic pattern.
The person's muscles are completely relaxed. If sitting up, the person may fall out of his or her chair as sleep deepens.
During sleep, the person occasionally rolls over or rearranges his or her body. This happens approximately once or twice an hour. This may be the body's way of making sure that no part of the body or skin has its circulation cut off for too long a period of time.
In addition to these outward signs, the heart slows down and the brain does some pretty freaky things.
In other words, a sleeping person is unconscious to most things happening in the environment. The biggest difference between someone who is asleep and someone who has fainted or gone into a coma is the fact that a sleeping person can be aroused if the stimulus is strong enough. If you shake the person, yell loudly or flash a bright light, a sleeping person will wake up.
Our Sleeping Patterns
There are four kinds of waves that a person generates: alpha, beta, theta, and delta. Alpha waves are what an awake and relaxed person generates, which are consistent oscillations at about 10 cycles per second. Beta waves are generated by an alert person, which are about twice as fast. Theta waves and delta waves take over while you are asleep and they are much slower. Theta waves have oscillations in the range of 3.5 to 7 cycles per second, and delta waves have oscillations of less than 3.5 cycles per second. As a person falls asleep and sleep deepens the brain wave patterns slow down. The slower the brainwave patterns, the deeper the sleep— a person deep in delta wave sleep is hardest to wake up.