Hypocapnia

Hypocapnia is an abnormally low level of carbon dioxide (CO₂) in the blood, usually caused by breathing faster or deeper than the body needs. In breathwork, this temporary drop shifts blood pH and can cause light-headedness, tingling in the hands or muscle tension that fade when breathing slows.

CO₂ is not just a waste gas: it helps regulate blood pH, blood-vessel width and the release of oxygen to tissues. Lower CO₂ narrows blood vessels in the brain, which is why light-headedness is so common in intense breathing. Symptoms that persist after breathing has calmed down, or chest pain and fainting, need medical attention.