The sleep stages

What are the sleep stages ?

A sleep consists of a number of cycles which succeed one another.
Each lasts about ninety minutes, and our sleep is so divided into equal periods of about half past one. These periods are themselves divided into several phases.
 Light sleep stage or stage 1from the sleep stages . At the usual time you go to bed, the brain releases a hormone, serotonin, which causes drowsiness,

yawning, itchy eyes. If you go to bed at that time, you fall asleep easily. This stage is very short and characterized by small sudden spasms and small muscle twitching, while the pulse and breathing slow down, become very regular and body temperature lowers. At this time, we do not dream yet, only a few images we pass through the mind, and the slightest noise wakes us up.

Light sleep to deep sleep, stage 2, much longer represents a transitional stage. The brain activity is reduced, the net loss of sensation is but a slight noise is likely to cause alarm.

The truly deep sleep stage 3 or installed. During this phase, you are almost completely isolated from the outside world, and it is difficult to wake you. The muscles are completely relaxed, the temperature is very low, breathing slow and steady. It is in this period that may arise from sleep disorders such as sleepwalking.

The "REM" or stage 4 is the phase most astonishing body seems totally relaxed and muscles relaxed as in deep sleep, but at the same time, brain activity is very intense.

Under the eyelids, the eyes are animated very fast movements, an erection occurs often in man and woman's clitoris enlarges, pulse and respiration are irregular.

This period of REM sleep is when you dream so intense.



It represents on average 20% of total sleep time for a normal night, but its duration is longer as the night progresses. Short during the first cycles, it can extend more than twenty minutes in the fifth or sixth. This means that the more we sleep, we dream more, and vice versa.

When awakened during this period, most people can easily describe their dreams or nightmares, citing specific details.

 What is the role that these sleep stages can play

However, sleep may play a positive role in the storage and retention.

For example, some studies have shown that when you do learn words, early in the day a group of individuals, and just before sleep to another, we see that this is the second group that s' remembers best the next day. It must be admitted that sleep is essential for integration of knowledge, insofar good sleep combats stress, which affects memory.

Unfortunately, this perspective was abandoned, partly because the amount of information disseminated and could actually be used by the student totally passive, but also because it seemed very difficult to match precisely the time information dissemination with the exact time of REM sleep. And I hope this articles helped you to have an idea about the sleep stages .