A couple of you guys sound like you have medical backgrounds. I don't.

A couple of questions: what happens to blood pH during really vigorous exercise? Does dissolved CO2 (carbonic acid?) cause the pH to go more acidic? Does this have an effect on the hemoglobin oxygen saturation curve? Maybe that's why a really committed athlete can force his PO2 sat to drop?

I wish I had some time to delve into this... I simply don't right now (I'm a working stiff, and...).