This article by Peter M. Litchfield, Ph.D. describes CapnoLearning, an approach using capnography and behavioral learning principles to identify and retrain learned breathing behaviors that compromise respiratory chemistry and acid-base balance. It explains physiological bases (Henderson-Hasselbalch equation, PaCO₂/ETCO₂ ranges, Bohr effect), defines behavioral hypocapnia with numeric ETCO₂ thresholds, catalogs symptoms linked to hypocapnia, presents a clinical case illustrating assessment and biofeedback-based retraining, and discusses efficacy and literature foundations.
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Peter M. Litchfield, Ph.D.; published in Psychophysiology Today, 2010, Vol. 7, No. 1.
Approximately 35–45 mmHg (target eucapnic respiration ~35–40 mmHg in training).
ETCO₂ readings below 35 mmHg: 30–35 mmHg mild–moderate, 25–30 mmHg serious, 20–25 mmHg severe.
Plasma pH normal range 7.35–7.45.
Total atmospheric pressure 760 mmHg; PO₂ ≈159 mmHg (20.93%); ambient PCO₂ ≈0.3 mmHg (<0.04%).