Correction of hypocapnia in hypoxic humans using biofeedback of alveolar carbon dioxide pressure

: Reactions of the respiratory system to the inhalation of a hypoxic gas mixture were compared when the test subjects (young healthy men) practised normal breathing or breathing with a stable alveolar PCO2. In the latter case the test subjects controlled their lung ventilation using the biofeedback technique. In this manner hyperventilation and related hypocapnia were eliminated. The possibility of practical application of biofeedback to the control of man's respiration in situations that may cause hypocapnia is discussed.