hyperventilation

Hyperventilation means breathing more than the body's metabolism actually requires. The defining feature is not how fast it looks but its result: arterial carbon dioxide is blown off faster than the body makes it, so its level in the blood falls.

Because carbon dioxide forms acid in the blood, removing too much of it makes the blood more alkaline, a state called respiratory alkalosis. The lower carbon dioxide can constrict blood vessels in the brain and shift calcium binding, producing the classic symptoms of light-headedness, tingling around the mouth and fingers, and muscle cramps even though oxygen levels are normal or high.

Hyperventilation can be a normal response, for example to exercise, pain, fever, or high altitude, or a sign of disease such as a clot in the lung, sepsis, or metabolic acidosis where deep breathing is compensatory. It may also be driven by anxiety. Distinguishing a benign cause from a dangerous one rests on the clinical picture rather than the breathing alone.