This article briefly discusses capnography and the use of individually meaningful psychological stressors (IMPS) to provoke episodes of acute hyperventilation. Guidelines are provided on history taking, and a strategy for using IMPS with ongoing capnographic monitoring is described, together with a proposal for diagnostic criteria. Diagnosis of hyperventilation using IMPS and capnography can help to demonstrate that feelings, breathing, and symptoms are all interlinked, and may help to suggest appropriate targets for therapy.