Kinetic aspects of singing.

Abstract

We analyzed events during singing, together with esophageal and gastric pressures, in pressure-volume diagrams. During singing and talking up to 90% of the vital capacity may be used without conscious efforts to increase tidal volume. Subglotic pressure (Ps) was obtained by subtracting, from pleural pressure (Ppl), the static lung recoil pressure at the same lung volume. Ps increased with loudness when sustained tones were sung; airflow rate increased in 2 and decreased in one subject. A steady Ps during sustained tones requires a continually and gradually changing effort, at first inspiratory and finally entirely expiratory. During singing of soft tones the diaphragm is often relaxed even though net inspiratory muscle effort is required. Apparently, the actions of the diaphragm and of other inspiratory muscles may become dissociated during singing in the upright posture: To maintain Ppl below relaxation values, even though the diaphragm is relaxed, inspiratory muscles other than the diaphragm increase rib-cage volume, the relaxed diaphragm ascends, the zero reference level for abdominal pressure descends, and the decreased Ppl is balanced by an increased hydraulic pull of the abdominal contents upon the diaphragm.