katyzzzSleeping and Working
August 8th 2006 01:44
The different stages of sleep
Sleep is one of the funny things about being a human being.
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.
Different animals sleep in different ways. Some animals, like humans, prefer to sleep in one long session. Other animals (dogs, for example) like to sleep in many short bursts. Some sleep at night, while others sleep during the day.
Sleep and the brain :
If you attach an electroencephalograph to a person's head, you can record the person's brainwave activity. An awake and relaxed person generates alpha waves, which are consistent oscillations at about 10 cycles per second. An alert person generates beta waves, which are about twice as fast.
During sleep, two slower patterns called theta waves and delta waves take over. 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 brainwave patterns slow down. The slower the brainwave patterns, the deeper the sleep -- a person deep in delta wave sleep is hardest to wake up.
The Reason for Sleeping :
No one really knows why we sleep. But, there are all kinds of theories, including these:
Sleep gives the body a chance to repair muscles and other tissues, replace aging or dead cells, etc.
Sleep gives the brain a chance to organize and archive memories. Dreams are thought by some to be part of this process.
Sleep lowers our energy consumption, so we need three meals a day rather than four or five. Since we can't do anything in the dark anyway, we might as well "turn off" and save the energy.
Dreams :
The brain creates dreams through random electrical activity. Random is the key word here. About every 90 minutes the brain stem sends electrical impulses throughout the brain, in no particular order or fashion. The analytic portion of the brain -- the forebrain -- then desperately tries to make sense of these signals. It is like looking at a Rorschach test, a random splash of ink on paper. The only way of comprehending it is by viewing the dream (or the inkblot) metaphorically, symbolically, since there's no literal message.
This doesn't mean that dreams are meaningless or should be ignored. How our forebrains choose to "analyze" the random and discontinuous images may tell us something about ourselves, just as what we see in an inkblot can be revelatory. And perhaps there is a purpose to the craziness: Our minds may be working on deep-seated problems through these circuitous and less threatening metaphorical dreams
Tips to improve one's sleep :
Exercise regularly. Exercise helps tire and relax your body.
Don't consume caffeine after 4:00 p.m. or so. Avoid other stimulants like cigarettes as well.
Avoid alcohol before bedtime. Alcohol disrupts the brain's normal patterns during sleep.
Try to stay in a pattern with a regular bedtime and wakeup time, even on weekends.
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