Sleeping, why do we do it?

To sleep. Why do we sleep and what happens when we sleep? This article describes the five stages: the hypnagogic state, light sleep, deep sleep, deep sleep and REM sleep.

Why do we sleep?

The idea that sleep is necessary to repair the body is not entirely true because everything remains active during sleep. Sleeping also costs energy and if you consider that if you sleep too little you can concentrate less well, you can think less well, you can react less quickly, etc., then sleeping is more about letting the brain rest.
Sleeping is necessary to process what you experience during the day and to sort out and organize your thoughts.

Sleep stages

  • Stage 1: Hypnagogic state
  • Stage 2: Light sleep
  • Stages 3 and 4: deep sleep
  • Stage 5: REM sleep


Stage 1: Hypnagogic state

When you close your eyes for a few minutes, the first phase of sleep begins. This phase is between being awake and sleeping. This phase lasts about five to ten minutes and you can easily wake up from small sounds. Your muscles start to relax and sometimes you may feel like you are falling or tripping, which suddenly makes you wide awake. This scares you.

Stage 2: Light sleep

During this phase you really fall asleep. This phase can last a few seconds but also ten minutes. You can easily be woken up in this phase. The special thing about this phase is that if you are woken up in this phase you do not feel like you were asleep at all.

Stages 3 and 4: deep sleep

After about twenty minutes you will be in a deep sleep. Your whole body is then relaxed and your heart rate and breathing are calm and regular. It is difficult to be awakened in this phase. Then you no longer know where you are and you want nothing more than to go back to sleep. In this phase, your body is probably completely recovered from everything you experienced that day. If you are still growing, a growth hormone is secreted during this phase of sleep.

Back to stages 3 and 2

After this you go back to stages 3 and 2. It took about 90 to 120 minutes before you started.

Stage 5: REM sleep

If you look at the brain of the person who is sleeping during this phase, it appears as if the person is awake. Your blood pressure rises again and your eyes start to move back and forth quickly while your eyes are closed. Your body is completely paralyzed. This is to prevent you from actually carrying out the dreams. The first REM phase lasts about 10 minutes before you move on to the next phase.


This cycle continues all the time until you get up. Each cycle takes longer and longer. For example, the last REM sleep can last up to an hour. This cycle is different for everyone. In general, a cycle lasts 90 minutes, about 4 to 5 times a night.


You probably know this. For example, think of your father snoring on the couch. People who snore can be very noisy. This occurs when the roof of your mouth and the back of your tongue almost touch each other, narrowing your airway.

Tips to try to prevent snoring:

  • Don’t sleep on your back.
  • If you are overweight, you can try to lose weight. Thicker people are more likely to snore because they have more tissue in the pharynx.
  • Drink little or no alcohol. This causes the muscles in your tongue and throat to relax.
  • Smoke less or not. Smoking thickens the mucous membranes in the throat.
  • Do not eat heavy meals before going to sleep.


read more

  • Theories about dreams through the years
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