Eli5: What is really happening when body parts “fall asleep” & why does the sensation feel that way?

Question

I undeestand it has to do with blood flow and such… but I’m curious why it feels tingly or even painful sometimes?

In: Biology

Answer 1

A lot of larger blood vessels travel in a similar pathway as nerves. When the blood vessels get constricted, there’s a fairly good chance that the nerves are too.

You get tingly and painful sensations because those same nerves are sensing irritation/damage from compression. When you compress blood vessels/nerves long enough, signals between the brain and various body parts don’t get sent causing your body parts to “fall asleep”. Kind of like getting a kink in a garden hose, depending on how bad it is, you could be slowing down or fully stopping the flow.

Keep in mind that if you compress or traction nerves for too long or aggressively, you will eventually get significant to even permanent damage to the nerves.