@JA10111
that's a misconception, human head (well, brains) still alive for some time (IIRC around 1-2 minutes?) and it still tried to "communicates" with other organs
So you actually feel the pain of getting decapitated, the blood loss, and suffocated at the same time
That's why there's no execution by decapitation since many years ago, it's inhumane. Executed by gunshot is actually better (if done correctly) since the shock to the body will make you passed out and you die without knowing it.