The reduction in pulmonary diffusing capacity after exercise was not alleviated by altering body position, and was primarily due to a decrease in pulmonary capillary blood volume. Although the mechanism for the reduction in Vc cannot be determined from these data, passive relocation of blood to the periphery as the result of gravity can be discounted, suggesting that active vasoconstriction of the pulmonary vasculature and/or peripheral vasodilatation is occurring after exercise. There was a similar pattern of change over time for Dlco, Dm, and Vc in the two positions.Ĭonclusions-The change in Dlco after exercise appears to be primarily due to a decrease in Vc.

The supine position produced significantly higher values over time for Dlco (5.22 (0.13) v 4.66 (0.15) ml/min/mm Hg/l, p = 0.022) and Dm (6.78 (0.19) v 6.03 (0.19) ml/min/mm Hg/l, p = 0.016), but there was no significant position effect for Vc. Results-After exercise, Dlco, Dm, and Vc were significantly depressed compared with baseline in both positions. Methods-Before and one, two, and four hours after incremental cycle ergometer exercise to fatigue, single breath Dlco, Dm, and Vc measurements were obtained in 10 healthy men in a randomly assigned supine and upright seated position. Objective-To investigate whether measurement position affects this impaired gas transfer. Background-Pulmonary diffusing capacity for carbon monoxide (Dlco), alveolar capillary membrane diffusing capacity (Dm), and pulmonary capillary blood volume (Vc) are all significantly reduced after exercise.

Breath by S. Atzeni