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Stages of Sleep

There are different stages of sleep that are divided into Non-Rapid Eye Movement (Non-REM, no dreams) and Rapid Eye Movement (REM) sleep.

Non-REM Stage 1. Light Sleep – think about the time when you are in class and your eyes fight to stay open. Your muscles begin to relax and the world around you starts to fade away as your brain activity slows down. You can be easily woken up from this stage or you might notice that you jump and wake yourself up when in this stage.

Non-REM Stage 2. Beginning of Sleep – still quite a light sleep, but your body is preparing for deeper sleep. (Normally the first 15-30 minutes of sleep). Your muscles continue to relax and your brain activity slows, but if the phone rings, the TV is too loud or someone calls your name you are likely to still hear it and wake up.

Non-REM Stage 3. Slow Wave Sleep – (Normally about 45 mins after you have fallen asleep).  This is most commonly known as “deep sleep”. Your brain activity has slowed considerably and your muscles are relaxed. It will be harder to wake up from this stage of sleep – you may feel disorientated and groggy if woken. This stage of sleep is when people are most likely to suffer from sleep related breathing disorder such as sleep apnoea.

REM stage.  This is when you dream and when your brain is most active but your muscles are at their most relaxed. In fact, most of your muscles (except heart and lungs) are paralyzed during this stage of sleep. Sometimes if people are woken abruptly from this sleep it may take a few seconds for them to be able to move – this is known as sleep paralysis. This is nothing to worry about. REM sleep is known to improve brain functioning and is when long term memories are created.

Figure 1

Sleep toolkit image 1

Did you know……?

  • You move backwards and forwards between these stages of sleep during the night? Deep sleep is towards the beginning of the night and REM sleep towards the end.
  • We tend to sleep for approximately 90 minutes and then partially wake up – if nothing around us has changed we usually fall back into deeper sleep without noticing. However, if things have changed (like your duvet falling off!) then this is when we wake up. It means that it is normal to wake up every hour or so after a deep sleep, e.g. rub our eyes, change position)   but we often drift back to sleep without noticing.
  • The 90 minute cycle may also make it harder for us to fall asleep if we push through feelings of extreme tiredness to watch that final few minutes of our favourite show and then try to go to bed, as you may miss the peak of your sleepiness for that cycle. Sometimes it can be more helpful to do something else such as read a book before trying to fall asleep again. For example: