• atomicorange@lemmy.world
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    9 months ago

    It’s definitely not just seconds. Think about how long you can hold your breath, you’d be conscious for at least that long. You start getting brain damage after like 4 minutes without oxygen, and can live for maybe 6 minutes.

    Edit: I’m wrong here! See the reply for why.

    • MyEdgyAlt@sh.itjust.works
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      9 months ago

      I don’t think this is quite right. Read up on “time of useful consciousness”. I think if you exhale the air in your lungs and inhale oxygen-free air you’ll be out much faster than if you just held your breath. I’m not entirely sure if total pressure matters or partial pressure matters, but I’m quite sure that there will be some similar effect. I have found some claims that the partial pressure is the major factor, so breathing pure nitrogen seems like it would incapacitate someone faster than holding their breath does, because the nitrogen is actively removing oxygen from their blood.

      • atomicorange@lemmy.world
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        9 months ago

        You are totally right. I looked into it a bit, the mistake I made was assuming that we’re more efficient at extracting oxygen from the air than we actually are. A held breath contains quite a lot of usable oxygen, which we can extract over minutes of time. Breathing in nitrogen would rapidly replace that still fairly-oxygenated air with pure nitrogen, and evidently our blood doesn’t carry more than a few seconds worth of oxygen.

        Thanks for the gentle correction!