The 4 Different Stages Of Sleep Simplified

Author: Halcyon Dreams Team   Date Posted:26 September 2017 

Until the 1950’s, scientists believed that sleep was simply our bodies and minds going into shut down mode, and that there wasn’t much more to it.


Nowadays this seems hard to believe as most people are quite aware that there is a difference between the foot-jerking stage of light sleep and the stage where it would literally take a ship horn in the bedroom to wake you up!


It wasn’t until fairly recently and after numerous tests that it was officially confirmed that we go through a number of different stages of sleep: four to be exact.


These four stages of sleep are characterised into two separate groups of REM and non-REM sleep. REM is an acronym for Rapid Eye Movement and it is the deepest form of sleep.


If you’ve ever been curious about what really happens when you turn in for the night, the following are the four stages of sleep that your brain and body experience throughout the night.


NREM Stage 1


As you fall asleep, have you ever felt your legs or body jerking like you are having a fit of some kind? This jerking reaction is a characteristic of the first stage of NREM sleep that can occur between 1 and 10 minutes after closing your eyes.


Your breathing slows down and your heartbeat becomes regular; your blood pressure and brain temperature will start to lower. If you’re woken during this stage of sleep, chances are you won’t even feel like you closed your eyes. You have basically just started to nod off.


NREM Stage 2


After about 10 minutes of sleeping you will start to enter the second stage of NREM sleep. This stage usually lasts around 20 minutes and is a little deeper than stage 1. Your heart rate will slow down even more and your body temperature begins to cool in preparation for deeper sleep.


Your brain also starts to emit larger waves and your blood pressure and other metabolic functions start to slow. It’s harder to wake up in stage 2 than in stage 1 however you are still likely to react to external stimuli like the smell of bacon coming from your kitchen.


Stage 1 and 2 for NREM sleep are usually lumped together and called “light sleep”. For those who like an afternoon nap, NREM stage 2 should be the deepest stage you want to enter. This will ensure that you don’t wake up too groggy. It is a quick brain recharge as such. Just remember to set your alarm before you fall into a deeper stage of sleep. We recommend 20-30 minutes as the optimum nap time. 


NREM Stage 3


Stage 3 of NREM sleep is also known as slow wave or Delta sleep, and this is the stage where your sleep starts to get serious.


It typically occurs 35 to 45 minutes after falling asleep when your brain has slowed right down. Stage 3 is the first phase of your brain entering into its restorative mode. It is processing the days information and cementing memories. Most of us have heard the phrase “Let me sleep on it” however we probably haven’t read too much into what our brains are actually going through when we sleep.


Sleeping on something you are having trouble making a decision about is much more than just taking a little more time. You are allowing your unconscious brain to process the information it has been fed on any given day. It can be quite satisfying to wake up with a new found clarity after a good nights sleep, especially for the procrastinators among us!  


REM Stage 4


Stage 4 REM sleep is the deepest form of sleep. Adults spend around one quarter of their night in this stage. While sleep research studies are not yet medically proven, it’s believed that Rapid Eye Movement (REM) is related to the internal images that your brain is creating whilst in its deepest form of sleep. Your eyes are literally darting around in various directions under your eyelids when you are in REM stage! 


Have you ever had a really vivid dream that almost felt real? If so, it’s likely you were dreaming whilst in stage 4 REM sleep. Other than ensuring essential bodily functions such as breathing and a regular heartbeat, your brain has now ceased controlling non-essential parts of your body such as your muscles, which have basically entered a paralysed state. Old sleeping sayings such as “Dead to the world” and “I slept like a log” come to mind when we talk about Stage 4 REM.    


Studies on the brains activity while sleeping in Stage 4 REM show that brain areas associated with long term memory, memory consolidation and emotions are extremely active. Take a little time to ensure that your sleeping environment is set up to allow your brain to enter its deepest form of restoration so you wake up feeling refreshed and ready for the new day.


We hope this article gives you a better awareness of the different stages of sleep that your brain and body go through over the course of the night and highlights the importance of getting a good nights sleep.

Sweet Dreams!

The Halcyon Dreams Team

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