Heart rate response to held lung volume

Abstract

It has been shown that respiratory sinus arrhythmia correlates fundamentally with lung volume changes. The correlation with thoracic circumference changes is incidental and quantitatively unreliable. Extensive measurements on 1 subject and limited measurements on 4 other subjects demonstrate the existence of a systematic relationship between heart rate and lung volume under reasonably static conditions, a high heart rate corresponding to the expiratory position and a low heart rate to the inspiratory position. This relation has been described successfully with an exponential equation.