(Eli5) Is it possible to suffocate while still breathing?

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I read somewhere that the reason people feel the need to breathe because of carbon dioxide building up in the body. So if you were to be per say in a room filled with just pure oxygen or some other gas other then carbon dioxide, would it be possible to suffocate due to lack of oxygen without getting that tight feeling in your chest that compels you to breathe? I.e you’re still inhaling and exhaling, but you don’t feel the tight chest feeling, while simultaneously suffocating

In: Biology

Yes, anything that displaces the oxygen in the air without adding carbon dioxide won’t be noticed. Hypoxia can hit pilots at altitude if they are not careful. It interferes with the brain so they don’t notice that they are not thinking clearly and becoming sleepy. Or look up OSHA’s rules and information on confined space entry. There is usually one or two incidents a year in the USA of workers being careless entering tanks, vaults or sewer pipes without checking the oxygen concentration. They pass out suddenly. Worse is when coworkers can see them and go in to try to get them out. Worst I’ve heard of is 5 guys one after the other. All dead within 30 feet of the entrance.

Yes, that’s a thing. It’s a not-unheard-of kind of industrial accident, especially in mines with poor ventilation. It happens when the air pressure is too low, too, like on Everest or in airplanes that lose cabin pressure.

But we usually call that *asphyxiation,* not suffocation. There’s not a strict rule about the words, but try to use suffocate when the victim uses up the available oxygen (or poisons themselves with their own exhaust), and asphyxiate when there isn’t enough in the first place.

> would it be possible to suffocate due to lack of oxygen without getting that tight feeling in your chest that compels you to breathe?

Yes. This is one of the big reasons the gas created by liquid nitrogen is so dangerous. It’s ordinary nitrogen, completely harmless, ordinary air’s over 70% nitrogen.

The danger is that the gas pushes out all the oxygen and you’re breathing a pure nitrogen atmosphere. Without the need-to-breathe warning signal, you keep on feeling normal until you pass out and die.

[Last month on ELI5](https://old.reddit.com/r/explainlikeimfive/comments/l79tv5/eli5_how_does_one_die_from_a_liquid_nitrogen_leak/) there was a question about a recent liquid nitrogen disaster that killed 6 people.

yes, and you wont even realize it without a co2 buildup (hypocapnic alarm)

thats why inert gas asphyxiation is commonly used for euthanasia of humans and animals alike