Some freedivers hyperventilate (breathe rapidly and deeply) before diving. Hyperventilation can change the concentration of CO 2 CO2 in the blood and may increase the length of time that a person feels like he or she can hold his or her breath. How does hyperventilation affect blood pH?

It is a state of breathing process when a person start breathing very fast. When a person is under excessive stress or he is paniky or he suffers from anxiety, he start breathing fast. Fast breathing results in excessive loss of carbon dioxide in the body.

Carbon dioxide forms acidic solution when dissolved in water. When level of carbon dioxide reduces in the blood, it becomes less acidic. In other words it becomes more basic. Therefore the level of pH of blood is increased.