alanf

Good point! I am with you and that's why I said it was a theory.

The CO2 and O2 that is in your blood from normal respiration and use by the body, is transferred by a chemical reaction in your lungs where the blood picks it up through I believe osmosis and chemical bonding between the iron in the blood, etc. (been awhile since I studied this stuff) So it's presence in the blood is in a very small state, as it is attached through a chemical bonding in an appropriate amount to the erythrocytes (blood cells that transport oxygen)

However my theory is that the carbonated water makes it's way through the gastointestinal tract and at some point it is picked up or transferred into the blood when the blood assumes that it is a liquid or water only and once in the blood stream, something happens that brings the CO2 out of the solution and as you see when a bubble forms on a soft drink after the top is removed, the bubbles start to come out of solution depending on whatever forces kept it there in the first place.

You'll notice that the bubbles in a glass of soft drink do not come out all at once, they come out slowly and it takes quite awhile for the last ones to bubble out of the glass, and if you shake it when it seems to be flat, you'll get more bubbles.

These bubbles could be conceivably large enough, that when they congregate somewhere like the heart and somehow make their way uphill to the brain, their presence there could block some areas from receiving oxygen or just their size in the minute blood vessels could cause the vessels to expand (causing pain) and also block blood flow and thus nourishment, which in the head (which is conceivably more sensitive) could result in a headache.

I remember seeing posters in the maintenance area of our flight operations that told of the dangers of guys goofing around or just not being aware of the danger of pointing a compressed air hose at any part of exposed skin. I initially thought it had to do with dust blowing into the person's eyes and then one of the mechanics explained the following;

This is because the extremely high pressure air coming out of the hose can (and has) forced it's way into the skin of the unsuspecting person and made it's way through the blood vessels into their heart and caused a fatality, or at least serious damage because the heart is a very strong pump and if it goes to push on what it assumes is heavy blood, but is really light air, it cavitates, misfires or whatever.

Sort of like if air leaks into a high pressure pump like a fuel pump in a PT6 engine or if you run a high speed propeller in a motorboat in a mixture of air and water, or you run a pump dry of whatever it is pumping. The blades will erode very quickly in a weird pattern or the extreme flexing of the blades will exceed the design strength and cause some sort of self-destruction.

http://en.wikipedia.org/wiki/Cavitation

Obviously this CO2 (in a soft drink) is not a factor in causing the heart to cavitate or there would be people popping off regularly, because a lot of people drink it. I am giving the compressed air story to illustrate that the blood can carry large amounts of air or gases.

The air that you swallow when you eat quickly is not allowed into your blood (in large amounts) (I am guessing) because of osmotic pressure.(which is whole other story)