Why does hyperventilating cause a person to become unconscious?

[Mr Rayon]

...

[Kyrisch]

Let me Google that for you...

[Mokele]

The key is that respiration isn't just about oxygen - it's about disposing of exactly the right amount of CO2 to regulate blood pH. Dump too little CO2, and your blood becomes too acidic. Dump too much CO2 (as in hyperventilation), and your blood becomes too basic.

 

Because we're ultra-high-metabolism endotherms, when our respiration is lower than normal, we feel the oxygen debt long before the CO2 excess. But in hyperventilation, we can feel the importance of CO2 in blood pH regulation.