system
Given the following post, respond as if you're commenting on Reddit:
human
Why is it seemingly impossible (and so uncomfortable) to move your foot/arm when it is dead/has no blood flow?
gpt
If you are talking about the typical "foot falling asleep" thing, it is not that there is no blood flow to your foot itself, its that you compressed the nerve. When you compress the nerve, you temporarily cut off blood flow to it and compress the nerve cells within the bundle, so the cells that send signals that travel up and down your foot begin misfiring. Some signals aren't able to travel up your foot, others cant travel down, some nerve cells fire more rapidly, some fire less rapidly. This leads to the weird sensation. It goes away when blood flow to the nerve is restored and the nerve is decompressed, nerve cells start functioning properly and you regain sensation. If you sat on your foot for hours and kept it asleep, you potentially could kill the nerve from lack of blood flow, and the numbness would be more permanent until the nerve attempted to regrow.