system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Is it dangerous to fall asleep with your head under the covers, or will you instinctively wake and gasp for air if needed?
gpt
Unless your covers are made of plastic, you're not going to suffocate under them. But even if they did, you would wake up because your body reacts when there is a buildup of CO2 in your system.

When you here of people suffocating in their sleep due to a gas leak or whatnot, it is because the gas replaces the CO2 and O2 in your system, and our bodies aren't set up to react to that.