th3krackan t1_j1c7lo9 wrote on December 23, 2022 at 5:36 AM

Yes, when doing gas work we have to enter low oxygen areas with a breathing apparatus of course. The low oxygen doesn't affect your body. However without the breathing apparatus and no suitable oxygen to breath then your body will not be triggered to expel carbon dioxide and you will just not be able to breath at all which will lead to death. But to answer your question yes our bodies can tolerate 0 oxygen areas.

Skipp_To_My_Lou t1_j1d9b0w wrote on December 23, 2022 at 1:18 PM

>However without the breathing apparatus and no suitable oxygen to breath then your body will not be triggered to expel carbon dioxide and you will just not be able to breath at all which will lead to death.

Lungs work as simple gas exchangers; nothing "triggers" them to absorb oxygen or expel CO2. Atmospheric air has a higher concentration of oxygen than the blood in the lungs, thus oxygen will permeate through the membrane due the higher specific gas pressure on one side. Same thing but in reverse for CO2.

What you might have been thinking about is the mechanism that causes the body to feel the need to breathe, which is triggered by high blood CO2 rather than low blood oxygen. Since as long as there is a lower concentration of CO2 in the air compared to the blood CO2 will permeate across the membrane & leave the body, this mechanism won't see anything being wrong even in an oxygen-deficient atmosphere. This is why, for example, a vessel under nitrogen purge is so dangerous; if a worker enters one they won't feel like anything is wrong until they drop unconcious in about 30 seconds.

th3krackan t1_j1da7un wrote on December 23, 2022 at 1:26 PM

If you walked into a vessel under nitrogen purge could you physically take a breath of nitrogen in and out ? Or will your body just not respond. In the few seconds you'd have before you pass out of course

Skipp_To_My_Lou t1_j1db52e wrote on December 23, 2022 at 1:35 PM

Our atmosphere is mostly nitrogen already, so you probably wouldn't notice any difference. Since there would be a higher gas pressure of nitrogen in the air than in the blood, the lungs would absorb inhaled nitrogen, then because there would be a lower gas pressure of oxygen & CO2 in the air than in the blood the lungs would expel those gasses. The exchanging oxygen out part would happen in any oxygen-deficient atmosphere, like e.g. an argon purge or very thin air, like if an airplane's cabin depressurizes.