[cdavis]

Good question, its not an easy concept to understand. Excessive hyperventilation will drop your co2 level so low that your carotid arteries contract, reducing blood flow to the brain and you see stars, tingle, etc. That is probably far below the level of co2 you should dive with.

Another off the wall idea. If hyperventilation can increase o2 supplies, could you make those o2 supplies available by breathing a gas mix of higher co2, assuming you could get the mix right? Maybe rebreathe the same air for the last few breaths?

Connor