Yes, but as you hinted at the human body can detect a rise in CO2 levels and it doesn't take much for things to start getting really uncomfortable and fast. To

Yes, but as you hinted at the human body can detect a rise in CO2 levels and it doesn't take much for things to start getting really uncomfortable and fast. To your point, if you could somehow manage the CO2 levels then you would just peacefully fall asleep and die.