Restricted postexercise pulmonary diffusion capacity and central blood volume depletion

Abstract

Hanel, Birgitte, Inge Teunissen, Alan Rabøl, Jørgen Warberg, and Niels H. Secher. Restricted postexercise pulmonary diffusion capacity and central blood volume depletion. J. Appl. Physiol. 83(1): 11–17, 1997.—Pulmonary diffusion capacity for carbon monoxide (Dl CO), regional electrical impedance (Z0), and the distribution of technetium-99m-labeled erythrocytes together with concentration of plasma atrial natriuretic peptide (ANP) were determined before and after a 6-min “all-out” row in nine oarsmen and in six control subjects. Two and one-half hours after exercise in the upright seated position, Dl CO was reduced by 6 (−2 to 21; median and range) %, the thoracic-to-thigh electrical impedance ratio (Z0 thorax/Z0 thigh) rose by 14 (−1 to 29) %, paralleled by a 7 (−3 to 11) % decrease and a 3 (−5 to 12) % increase in the thoracic and thigh blood volume, respectively. These responses were associated with a decrease in the plasma ANP concentration from 15 (13–31) to 12 (9–27) pmol/l ( P < 0.05). Similarly, in the supine position, Z0 thorax/Z0 thighincreased by 10 (−5 to 28) % when Dl CO was reduced 12 (6–26) % ( P < 0.05), whereas Dl COremained stable in the control group. The increase in Z0 thorax/Z0 thighand the corresponding redistribution of the blood volume in both body positions show that approximately one-half of the postexercise reduction of Dl CO is explained by a decrease in the pulmonary blood volume. The role of a reduced postexercise central blood volume is underscored by the lower plasma ANP, which aids in upregulating the blood volume after exercise in athletes.