It's more than that. Hemoglobin will preferentially release Oxygen in low pH (acidic) conditions and take up Oxygen in high pH (alkaline) conditions. CO2 in the

It's more than that. Hemoglobin will preferentially release Oxygen in low pH (acidic) conditions and take up Oxygen in high pH (alkaline) conditions. CO2 in the blood increases acidity, so the result of this behavior is that hemoglobin will release Oxygen in parts of the body where CO2 concentrations are higher and will pick up Oxygen in areas where CO2 concentrations are very low. If you hyperventilate then you remove CO2 from your blood, reducing its ability to deliver Oxygen to tissues due to reduced acidity. This conditions, called hypocapnia, leads to vasoconstriction of blood vessels in the brain, which can cause even lower Oxygen uptake in the brain, as well as bronchoconstriction. This can cause you to blackout and can, in combination with the mechanism you've described, result in decreased ventilation when breathing resumes.