How the body knows what to avoid doing while sleeping

Question

So this one came to me after a miserable weekend after surgery, I had a foley catheter in (its a catheter that is anchored in the bladder with a water balloon and is connected to a pee drainage bag), and in order to sleep I had to connect a big overnight pee bag and put it next to my bed. Now, I’m an active sleeper, I roll around and change positions a ton, so I was terrified of rolling over in my sleep and potentially yanking the catheter out, which would have been extremely painful at \*best\* and probably damaged my insides at worst.

Weirdly though, I slept still as stone, I barely moved for the 3 nights I had it in and I had no issues whatsoever. I’ve also noticed I do this if I fall asleep with my glasses or phone right next to me, I subconsciously avoid rolling over them in my sleep somehow and don’t move around as much.

How does that work? How does an unconscious body “understand” a danger/risk and avoid it?

​

​

In: 552

Answer 1

From u/OnionSquire on a similar post from 9 years ago:

“When you sleep your body releases a neurotransmitter called gamma-aminobutyric acid (GABA). What GABA does is effectively paralyze your body, or at the very least, your brains ability to move muscles. This occurs during REM sleep when you’re dreaming; it’s to prevent you from acting out your dreams, your body expends next to no energy in this state and consumes very little oxygen. This is only one reason why you don’t fall off the bed though. REM sleep, when you’re actually dreaming, only happens in 90 minuet intervals and only lasts a precious few minutes. So that dream you had where you were skate boarding down a big hill that lasted for hours, only took up a few moments of your actual time.

There are 5 stages to sleep. N-REM 1, N-REM 2, N-REM 3, N-REM 2 again, and REM. During this cycle, outside of REM, your body and mind are effectively awake. You’re not aware of your surroundings, but you’re aware enough to know when there’s an edge near you, or a predator, and you move away. Incidentally, if you ever get the feeling like you’re falling when you’re going to sleep, this occurs in N-REM 2 where “sleep spindles” happen. A sleep spindle is a sudden massive burst of neural activity that usually jolts a muscle and wakes a person.”