Hyperventilation syndrome: measurement of objective symptoms and subjective complaints.

In 303 subjects, amongst whom 250 patients suspected of suffering from the hyperventilation syndrome, lung functions were measured, a hyperventilation provocation test was performed and a questionnaire was taken. The subjects were subdivided into categories of nonhyperventilators, and 3 categories of hyperventilators, on the basis of objective measurable lung function parameters and the result of the provocation test. The outcome of the questionnaire in the various categories was evaluated. Some subjective complaints were related to age, sex, PaCO2 and lung function of the subjects. There was no clear correlation between PaCO2 and neurological signs. Hypoventilation after the provocation test occurred in only 5 subjects. No indications were found that hyperventilation might be an early sign of chronic obstructive lung disease.