It’s believed we need sleep because of a waste product called adenosine builds up in our brains while we’re awake. When we’re unconscious the waste stops building up and the CSF in the brain gets rid of it. Adenosine is a CNS depressant and works on the same receptors as sleeping pills so wouldn’t it be like the idea of holding your breath until you die, you’d just involuntarily pass out (as if you’d been given anaesthesia) and the problem would solve itself? I’m imagining a CNS depressant would cause unconsciousness long before it got to lethal levels.
When people have tried this they found you can’t just stay awake. Your brain ends up turning bits of itself off at a time, so while you can talk and move around you’re basically not fully conscious and will mix up words or not be able to move at the same time. They called it “microsleep”, and it’s the main reason why nobody tries to go for longer without sleep any more: beyond a certain point you’re not really awake or asleep.
I did 2 days once and I dont remember the hour long drive home from work at the end.