Can our bodies tolerate environments without oxygen?

Submitted by purvel t3_zsxwdb in askscience

What I mean is, if we have access to a normal breathing atmosphere through some sort of breathing apparatus, would our bodies otherwise tolerate being in an atmosphere (same pressure as normal) devoid of oxygen? The only answers I was able to produce while searching related to what happens to our bodies in space or on different planets, and that our skin doesn't "breathe", but still absorbs oxygen.

So just as an extreme example, if we were to find another planet with the same pressure and composition as ours but lacking oxygen, or if our own somehow ran out of oxygen, would there be a limit to how long we could stay outside without a suit, aside from the oxygen required to breathe?

Or in other words, what would happen to our bodies if the respiratory system was the only part of us that had access to oxygen (most of the time)?

(not sure if right tag)

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team-tree-syndicate t1_j1bypur wrote

As long as your body intakes normal air, and the atmosphere outside is the same pressure as our atmosphere, then I would think that nothing of significance would happen. Being submerged in water and having a breathing apparatus, but not a full diving suit is possible already, so long as the pressure differential isn't significant. Breathing pressurized air deep underwater and then rising up too quick is dangerous due to gas expansion, as well as nitrogen saturation. As for long term side effects, I don't believe it has been tested before in a study. Could be wrong on this though.

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CleverName9999999999 t1_j1c3ivq wrote

There have been designs for counter pressure spacesuits that keep the body under pressure from the tension built into the material of the suit. The head would be surrounded by a breathable atmosphere but the rest if the body would be in vacuum. Tests show they’d be quite effective.

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th3krackan t1_j1c7lo9 wrote

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.

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destinationlalaland t1_j1c9cqe wrote

People enter various types of IDLH (immediate danger to life and health) environments every day. They range from toxic gasses to low oxygen and everywhere in between. If none of the hazards are absorbed through the skin, game on. Limit is your air supply and shift change. Only thing stopping a person from porky-pigging it most of the time is company specific policy and your local indecent exposure ordinances.

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die_kuestenwache t1_j1ca1bc wrote

From a breathing point of view, yes, we would be fine. The whole "we need to also breathe through our skin or else we die" thing is bunk. However a lot of atmospheres might be otherwise toxic and cause problems to our skin or mucus membranes without a hazmat-suit. It wouldn't have to be pressurized though.

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gruntbuggly t1_j1ce9ue wrote

As long as you have oxygen in the air supply to breathe, you would survive a no oxygen atmosphere. For example if you made an atmosphere that replaced all of the oxygen with more carbon dioxide, argon, and helium, you could walk around in that all day long, with a scuba tank and a regulator. Your skin doesn’t need the oxygen in the atmosphere, but all the metabolic processes in your body require you to be able to breathe in oxygen.

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CrateDane t1_j1cztby wrote

Your corneas normally perform gas exchange directly from the air (well, via the tear fluid), rather than being supplied by blood, so your eyes would have a bit of a problem if the breathing apparatus did not cover them.

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Skipp_To_My_Lou t1_j1d9b0w wrote

Replying to th3krackan (#1,018,894)

>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.

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th3krackan t1_j1da7un wrote

Replying to Skipp_To_My_Lou (#1,021,617)

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

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Skipp_To_My_Lou t1_j1db52e wrote

Replying to th3krackan (#1,021,705)

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.

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curt15-club t1_j1dq477 wrote

Replying to team-tree-syndicate (#1,018,103)

Yup, for anyone interested, many SCUBA divers use wetsuits which trap a layer of water inside that your body heats up to keep you warm even in somewhat cold waters. Drysuits keep the water out but are less comfy and are for more extreme cold temps, usually < 50°F (you get cold faster in water so even 50° is dangerous if unprepared)

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purvel OP t1_j1wmfzf wrote

Replying to destinationlalaland (#1,019,040)

I've actually practiced going into such environments a little bit through work, and it's part of what makes me curious. I wonder how long our bodies could tolerate it. It would be interesting if oxygen through the lungs was enough on a long-term basis!

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