Course Content
Sleep Well Coach Training
About Lesson

There are 4 stages of sleep, determined by brain activity, which impact upon the quality and restorative nature of the sleep we are getting:

Stage 1 non-rapid eye movement (NREM) also referred to as N1 lasts from 1-7 minutes occurs when a person first falls asleep. The body has not fully relaxed though the brain and body activity starts to slow down. It is easy to wake someone up at this stage. 

Stage 2 NREM also referred to as N2 lasts for around 20 minutes where you become less aware of surroundings, body temperature drops, eye movements stop and breathing and heart rate become more regular. The brain produces sleep spindles (rapid rhythmic brain activity) thought to be feature of memory consolidation.

Stage 3 NREM also referred to as N3 is when we go into deep sleep and it’s harder to wake someone up in this stage. The brain produces delta waves which are slow wave brain activity, therefore this stage can be referred to as delta sleep or slow wave sleep (SWS). It is believed that this stage is crucial for body recovery, growth and to strengthen the immune system. We are in N3 between 20-40 minutes and more time is spent in deep sleep earlier in the night.

Stage 4 rapid eye movement (REM) lasts for 10-60 minutes. During this stage brain activity picks up to that seen when awake, however, the body experience atonia which is a temporary paralysis of the muscles apart from the eyes and the muscles associated with breathing. You can observe the eyes moving rapidly under the eyelids in this stage hence the name. REM is believed to be essential to memory, learning and creativity and is known for vivid dreams. We have more REM sleep in the later half of our sleep.

These stages make one sleep cycle of an average time of 90 minutes. We cycle through these between 4-6 stages throughout the night, although we don’t spend exactly the same amount of time in each stage in each cycle. The duration of time in each stage and the various cycles are referred to as sleep architecture, a sleep specialist may show you this on what’s known as a hypnogram—a graph produced by an EEG.