Physiological Alterations in the Pulmonary Capillary Bed at Rest and During Exercise

Abstract

The reactivity of the pulmonary capillary bed during exercise as estimated by change in the pulmonary diffusing capacity (D l _co ) has been shown to be dependent upon at least two separate mechanisms. The initial (0 to 10 second) D l _co rise with exercise appears to be volume-pressure dependent and may be altered by mechanisms influencing these factors in the lungs. The later elevation of D l _co with exercise was demonstrated to be primarily independent of the initial rise and uninfluenced by factors affecting peripheral venous return, that is body position and ganglionic blockade.