Changes in respiratory movements of the human vocal cords during hyperpnea

Abstract

Five healthy young subjects were studied to assess the changes in vocal cord movements that occur between resting breathing and hyperpnea. Both hypercapnia and exercise induced decreases in the extent of narrowing of the glottic aperture occurring during expiration. Of the subjects, 4 also showed a significant positive rank correlation between the extent of narrowing of the glottis and the observed length of the expiratory phase of the respiratory cycle. Apparently, braking of expiratory airflow by movements of the vocal cords towards the midline is reduced during hyperpnea at the same time that expiratory time is decreased.