"Australopithecus scobis" wrote in message
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On Sun, 09 Jan 2005 23:40:03 -0600, John A. Weeks III wrote:

No, I meant CO2.
But, but, your body won't start using CO2 "in place of" O2. Most you could
do is start driving aerobic metabolism backwards, but the Km is such
that you'd be dead of other CO2 effects before that caused any harm.
Really. Carbon monoxide does directly replace O2 in hemoglobin.

I'm not disagreeing with you that CO2 in high concentrations is a Bad
Thing. I'm quibbling about the biochemistry.

Well, quibble a bit on the physiology, too. Normally our breathing trigger
is CO2 level, so a rise in CO2 would cause an increased rate of breathing -
hyperventilation, rather than the insidious falling away that hemoglobin's
affinity for CO would cause. Easy to recover from, since CO2 can be blown
out of the blood fairly quickly, while CO hangs in for a long time even on
100% oxygen.

Now if you're a COPD type, triggering on O2 level, 'nother story.