CO2 is only a problem in your blood, not in your lungs. Exhaling won't diminish the C02 content of your blood. You would have to exhale repeatedly to get rid of excess C02. As a matter of fact, the increase in pC02 in your blood is what makes you want to breathe, not the oxygen content. That is why it is a mental game. The only danger is when you get so good at resisting the urge to breathe, when your C02 builds up, and eventually you DO have a problem with lack of oxygen, which will kill you. The C02 will eventually increase your acidosis, but not in that short a period of the apneia. I use to blow out some air, but after reading a lot, it seems reasonable to hold on to the air in your lungs for as long as you can, since the residual oxygen will be uplifted to the blood. That will help you to not pass out, but it won't prevent your need to breathe. billy fanstone
CO2 is only a problem in your blood, not in your lungs. Exhaling won't diminish the C02 content of your blood. You would have to exhale repeatedly to get rid of excess C02. As a matter of fact, the increase in pC02 in your blood is what makes you want to breathe, not the oxygen content. That is why it is a mental game. The only danger is when you get so good at resisting the urge to breathe, when your C02 builds up, and eventually you DO have a problem with lack of oxygen, which will kill you. The C02 will eventually increase your acidosis, but not in that short a period of the apneia. I use to blow out some air, but after reading a lot, it seems reasonable to hold on to the air in your lungs for as long as you can, since the residual oxygen will be uplifted to the blood. That will help you to not pass out, but it won't prevent your need to breathe. billy fanstone
