REM and Non-REM Sleep

 Sleep is perhaps the single most effective thing that we can do each and every day to reset the health of our brain and our body. By understanding a little bit more about what sleep is we can get the chance to improve both the quantity and quality of our sleep. 

What is sleep? Well sleep at least in human beings is subdivided into two main types.

1. Non REM (Rapid Eye Movement) Sleep.
2. REM Sleep

Non-REM Sleep:

Non REM sleep is further subdivided into 4 separate stages:

• Stage 1: Awake/Light Sleep
• Stage 2: Light Sleep
• Stage 3/4: Deep Sleep

As we go into the light stages of Non-REM sleep our heart rate starts to decrease, your body temperature starts to drop and your electrical brain wave activity starts to slow down but as we move into deeper Non-REM sleep that is the stages 3 and 4, all of a sudden the brain erupts with these huge big powerful brain waves. The body gets recharged in terms of its immune system, we also get this beautiful overhaul of our cardio-vascular system and upstairs in the brain deep Non-REM Sleep will help consolidate memories and fixate them into the neural architecture of the brain.

REM Sleep:

It is during the REM sleep that we have the most vivid and the most hallucinogenic types of dreams. The brain activity starts to speed up again and it's during the REM sleep that we receive all the forms of emotional first aid and we also get a boost for creativity that stitches information together so that we wake up with solutions to previously difficult problems that we were facing. 

Coming back to these two types of sleep, it turns out that Non-REM and REM will play out in the battle for brain domination throughout the night and the cerebral wall is going to win and loss in every 90 minutes and keeps replaying at every 90 minutes. It produces a standard cycling architecture of human sleep, a standard 90-minute cycle. The difference is, however, the ratio of Non-REM to REM within those 90 minutes cycle changes as we move across the nights such that in the first half of the nights the majority of those 90 minutes cycles are comprised of a lots of deep Non-REM sleep particularly the stages 3 and 4. As we move towards the second half of the night most of the 90 minutes cycles are comprised of REM sleep or the dream sleep. 

There are implications for understanding how sleep is structured in this way. Let's take an example of someone who typically goes to bed at 10 pm and wakes up at 6 am, and thus have an 8-hour sleep window. Let us suppose that this man who sleeps for an 8 hour has to wake early one morning for a meeting or anything and he/she woke up at 4 am instead of 6am. 

They have lost 2 hours in their 8 hours a regular night of sleep which means that they have lost 25% of their sleep. REM sleep comes mostly in the second half of the night particularly in those last few hours he/she has lost 60-70% of all of the REM sleep. And as a result you feel that you have not even slept the whole night.