Ever wondered what happens to your body when you close your eyes and fall asleep at night? Well, your body passes through exactly five different stages of REM (rapid eye movement) and NREM (non-rapid eye movement) sleep. Each stage serves a unique healing function, like muscle recovery and memory consolidation. This five-stage cycles repeats four to six times and each cycle usually lasts for an average of 90 minutes. The details of these stages are as below:

Stage 1

This stage is characterized by NREM sleep in which your body moves in and out of consciousness. You may be partly awake, which is why you may feel as if you haven’t slept at all once woken up. It is in this stage that one experiences hypnic myoclonia – the falling sensation while sleeping that instantly brings you back to consciousness.      

Stage 2

In this stage, one witnesses a light sleep. However, your body starts to prepare for a deep sleep since your heart rate relaxes and body temperature falls. Apart from this, eye movement stops and brain waves slow down including the sporadic burst of waves, known as sleep spindles.    

Stages 3 and 4:

Both of these stages are characterized by deep sleep. These stages are grouped together because they feature periods of slow wave sleep (SWS). The latter is the deepest sleep your body enters in the night and is so profound that if someone is woken up then they may feel cranky and confused. These stages are immensely revitalizing for the body as different hormones are released that help in growth and hunger control.

Stage 5

This is the only stage of REM sleep that a person experiences. The brain activity in this stage is the highest and one is able to dream. In REM sleep, a person’s mind reenergizes while the body becomes immovable. Heart rate and blood pressure begins to rise as opposed to other stages.

The five stages of sleep are crucial to rejuvenate oneself and understanding these stages can help us to sleep better at night.