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O2: How Much Do We REALLY Need?

  1. Dec 16, 2004 #1
    How much oxygen is absolutely required for the human body to survive?

    If it depends on time, how about for 6 months, until the original O2 levels are back.

    Earth is at, what, 23%? Could we survive on 8% for six months?
  2. jcsd
  3. Dec 21, 2004 #2


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    Last edited by a moderator: Apr 21, 2017
  4. Dec 27, 2004 #3
    Wow! I never would've thought...
    And that's an excellent link, too. Thanks.

    My next question: How much O2 is too much? I found this in your link;
    Is that the only problem? Is there a threshold on the amount of oxygen before it becomes a safety/flammability issue?

    Could we have O2 at 50%? Would there be any benifits to breathing at increased O2 levels (memory, extended work times, concentration)?
  5. Dec 27, 2004 #4


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    There is such a thing as oxygen poisoning; too much oxygen can be quite harmful to the brain. Back when I did biology in college, my teacher mentioned this, and told us how breathing too deep and fast could make one feel rather giddy and unwell (which two members of my class proceeded to do, and then felt a little dizzy and ill. Don't try it.) I'm not sure exactly how this works. Perhaps this would be adressed better in the biology section.
  6. Dec 28, 2004 #5
    Hyperventilation (lit. too much breathing) blows off the carbon dioxide in the blood stream too fast, increasing the pH in the bloodstream (respiratory alkalosis.) Breathing in and out of a bag increases the amount of carbon dioxide inhaled and helps return the body chemistry to normal.

    Above a certain partial pressure, oxygen becomes poisonous. I can't remember what that value is, but I believe it's 1 or 2 atm. Hyperbarric chambers (which increase the total atmospheric pressure and thus the partial pressure of the oxygen) are used on severe burn victims (and if rumor is true, Michael Jackson sleeps in one. :rofl: )
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