What are the Different Stages of Sleep

The stages of sleep have been established through various demonstrations using electroencephalograph device which showed different patterns projected by brain of a human being about the sequence of stages through which it passes with the progress in sleep. The sleep is discovered to be of two kinds, quiet sleep or non-rapid eye movement (NREM) and paradoxical or active sleep or Rapid eye movement (REM)

Activation of sleep

While one goes to sleep, he is still alert and conscious. The active brain produces a kind of fast and small waves known as beta waves which slows down to be alpha waves while the brain begins to relax and goes to sleep. You will experience certain extraordinary and entirely glowing sensations called hypnagogic hallucinations, till your brain has not gone to sleep completely, which can be experienced by hearing certain sounds while you initially go to sleep. A myoclonic jerk is also a common even that is experienced severally when one suddenly wakes up without any apparent reason in the initial stage of sleep.

Different stages of sleep

The sleep can be divided into five stages.

  • Stage 1:
    It is the light stage of sleep which occurs in the initial stage when brain is neither at sleep nor fully awake but somewhere in between. Brain produces theta waves of high amplitude, the extremely slow waves of the brain, which lasts for not more than 10 minutes. The person in this stage poses to be not sleeping, if awaken.
  • Stage 2:
    In the second stage of sleep the brain produces large amount of rhythmic and rapid waves which activates the sleep and this stage lasts till 20 minutes. The temperature of the body starts reducing and the beat of heart slows down at this stage.
  • Stage 3:
    The brain produces delta waves, deep but slow waves, which help in deepening the sleep as the person at this stage is between the light and deep sleep.
  • Stage 4:
    The brain, at this stage also, goes on producing delta waves and the person remains at deep sleep. Sleep walking or bed wetting are usually experienced in this forth stage of sleep.
  • Stage 5:
    This stage of sleep is known as REM and the dreams occur at this stage. The activity of brain increases at this stage with a retrospective effect on respiration and eye movement. This stage is also known as paradoxical sleeping stage when brain is most active, when dreaming gets possible, but the muscles remain extremely relaxed.

The sleep do not progress sequentially from stage 1 to stage 5 but it repeats several times throughout the sleep in a cyclic way, from stage 1 to 4 and returns to stage 2, to prove REM which last for about 90 minutes every time. The period elongates with every rotation of the sleep cycle.

 

 

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