Information about Sleep

It is known that sleep is necessary for any humans and other animals to survive. There is not much dispute over that. There is not really a certainty about why it is necessary to survive, though 1/3 of our lives are spent sleeping. There are several different theories that people believe could be true to answer the question.

Here they are: The first is the "Adaptive Theory". This is an idea that states that it is needed for animals to thrive in their habitat's. Different animals have different habits that help them to adapt and survive in the environment.
A second one is the "Energy Conservation Theory". This is an idea that it is needed to conserve energy in the body, especially for the more active of animals.
A third theory is "Restorative Theory". Sleep is needed because certain things happen during sleep that don't happen as much in wakefulness. For example, certain hormones and chemicals are released during sleep during different stages, and they are needed to become full grown, healthy people. So, it would be needed to meet all of the the chemical requirements for our bodies.
The fourth theory is "Programming-Reprogramming Theory". This states that unimportant information is "erased". This is why it is thought that infants sleep more... because they're learning. But, it is not just sleep that seems important for this theory, but instead, REM sleep that could be the crucial part. It is shown that infants have more REM sleep than adults, but adults undergoing intense schooling also seem to experience an increase in their REM sleep. People with less REM sleep seem to be less adept to creative problem solving, suggesting even further the possibility in the truth to this theorem.

Stages of Sleep

There are several stages of sleep that run through cycles throughout the night. Scientists determine these stages according to the brain waves that are detected during sleep. As the cycles repeat, each stage becomes longer and longer, especially the REM stage.
Stage 1 is the shortest stage only lasting a few minutes. It is when the body is just drifting off to sleep. The brain waves are high amplitude, and some that are equivalent to wakefulness.
Stage 2 is deeper than stage 1. Your heartbeat and breathing slow down, and the brain waves are "slow-waves" with peaks in them.
Stages 3 & 4 are very similar except that Stage 4 is deeper than Stage 3. This is the deepest sleep. The brain waves are the slowest, and the breathing and heartbeat slow even more as the muscles relax. Dreams are more common in the stage, along with sleep walking and talking.
REM Stage (or Rapid Eye Movement Stage) the heartbeat increases and breathing becomes shorter. Obviously, your eyes move rapidly and your brain waves are similar to your wakefulness, but your muscles stay relaxed. This is when dreaming is the most vivid.

Sleep Disorders

There are many types of sleep disorders. Some of them, just to name a few are: Delayed Sleep Phase Disorder, Advanced Sleep Phase Disorder, Non-24-Hour Sleep-Wake Syndrome, Jet Lag, Shift Work, Obstructive Sleep Apnea, Narcolepsy, Restless Leg Syndrome (RLS) and Sleepwalking. To find out more about them see the extra information page.



Home Page

Next Page-Dream Information