why are we never aware of the exact moment we fall asleep?
In: Biology
**TL;DR** There’s no *exact* moment when a switch flips and you fall asleep. Instead, your conscious thoughts drift away until only sleeping thoughts are left over. Because some people have clear memories during sleep, a lot of people still think they are ‘awake’ until they enter REM sleep (and some still think they’re awake then). Some people train to keep conscious thinking while asleep, in order to remember or control their dreams.
EDIT: Thank you kind strangers, medals are always a welcome surprise.
Sleep is a very complex process, and neuroscientists have begun to understand parts of it quite well. But there’s still a lot of stories about it which are not researched well yet. Some of this comment will be old science, so if you are interested, definitely learn more from books and interviews by neuroscientists.
The process of falling asleep involves your brain slowly shifting gears into more relaxed operation. A common model is that the brain has ‘stages’ of sleep that look distinct on measuring devices.
Stage 0 would be ‘awake’ and you have a lot of conscious brain activity, observing surroundings and planning action.
As you relax, you enter stage 1, which still feels very awake to people. But during this stage, conscious brain activity shuts off and the brain only turns it back on sometimes (probably so threats and danger don’t catch you by surprise). During stage 1, your thought patterns load and re-experience memories without much conscious control over them.
Then stage 2 begins, and the bursts of ‘awake’ activity stop. Although at this point you have entered ‘sleep’, almost 40% of individuals still have clear enough memory to consider this ‘awake’ and not realize how much their brain activity has been affected. This is the type of sleep some call light sleep. You can be woken up from it more easily than the next stage, because your sense of the outside world is still on, but very slow. The next stage is called Rapid Eye Movement (REM) sleep.
Then two further stages (3 and 4) exist, which include the commonly called “REM sleep”. During these stages, you begin to dream and most of your conscious thoughts have turned off. These are often called deep sleep because you become much harder to wake up and feel groggy if someone does wake you up. These stages almost universally register as “asleep” to the sleeper.
You can train your thought patterns enough to have awareness and a vivid memory during stages 3 and 4 of sleep, in a process called lucid dreaming. Lucid dreaming allows you to (seemingly) wake up during dreams and change them with conscious thoughts. In addition, the training allows you to remember dreams clearly enough to keep a dream journal or interpret them. Lucid dreaming is still very poorly understood, however research is beginning to identify differences in brain activity that suggest how it occurs.
[This article](https://www.livescience.com/19462-fall-asleep.html) gave me some of the context to express the process in more detail.
[This 2019 research](https://pubmed.ncbi.nlm.nih.gov/30880167/) discusses current research about lucid dreaming and comes to a preliminary conclusion about which parts of the brain cause it.
Latest Answers