Aswad
Posts: 9374
Joined: 4/4/2007 Status: offline
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quote:
ORIGINAL: PeonForHer I was led to believe that well before someone falls unconscious, he's no longer able to hold his breath. Strictly speaking, this isn't necessarily true. You can hold your own breath until brain damage occurs, as demonstrated by pearl divers who will hold their breath for far longer than the brain can tolerate oxygen starvation plus the time the blood has a reservoir for. It will depend on the discipline (and, in extreme cases, stupidity) of the person who is holding their breath. We used to have a stupid game back in school to see who could hold their breath the longest. I can hold my breath for 6 minutes 40 seconds. That's past the safety limit of 6 minutes. Another 10-30 seconds beyond that is probably all it would take for me to pass out, at which point the part of the brain responsible for automatic breathing will most likely kick in as it should. However, it is driven by sensing the levels of CO2 and oxygen in your blood, and I have no idea whether this can be desensitized like other sensory nerves. Also, I do know that there are both drugs and medical conditions that suppress this reflex and/or the sensory input that drives it. Unless you've done a gene assay up front, you don't know if you're one of the people who will simply not start to breathe again while unconscious (though the chances are reasonably good). Never allow a person under your care to hold their breath for more than a few minutes. Health, al-Aswad.
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"If God saw what any of us did that night, he didn't seem to mind. From then on I knew: God doesn't make the world this way. We do." -- Rorschack, Watchmen.
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