Restricted postexercise pulmonary diffusion capacity and central blood volume depletion

Abstract

Pulmonary diffusion capacity for carbon monoxide (DLCO), 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, DLCO 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 thigh increased by 10 (-5 to 28) % when DLCO was reduced 12 (6-26) % (P < 0.05), whereas DLCO remained stable in the control group. The increase in Z0 thorax/Z0 thigh and the corresponding redistribution of the blood volume in both body positions show that approximately one-half of the postexercise reduction of DLCO 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.

Normovolaemia defined by central blood volume and venous oxygen saturation

“…To evaluate the volume within the thoracic region, including the central vessels and the heart, electrodes are positioned at the right side of the neck and as high as possible in the left mid-axillary line with an approximate 5 cm distance between each pair. With this arrangement of the electrodes, high correlations (r > 0.9) are derived to changes in the thoracic blood volume 10,60,67 and near perfectly matching values are obtained in experimental haemorrhage studies (Fig. 3).…”

“…Activation of the muscle pump is especially important following exercise, when blood accumulates in the distended veins of the legs and where the subject continues to hyperventilate. 60 The CBF is affected by the combined effects of lowering of the arterial carbon dioxide tension and a CO reduced by a low CBV. Because fatigue makes movement unattractive, the athlete feels better by lowering the head by leaning on their knees or when lying down, thus neutralizing the hydostatic difference between the heart and the brain.…”

“…This is of relevance because, immediately following exercise, blood has accumulated in the previously working muscles and, accordingly, CBV is reduced. 60 Similarly, thoracic electrical admittance is reduced, whereas that over the leg is enhanced. A similar situation develops after distal bypass surgery, where the admittance detects oedema of the operated leg in proportion to the determined swelling.…”

Effects of the order of running and cycling of similar intensity and duration on pulmonary diffusing capacity in triathletes

“…Wells et al (1987) demonstrated that the prior cycle bout induced a reduction in plasma volume that tended to be reversed during the subsequent run, whereas during a run-cycle succession the subsequent cycle bout maintained the reduced plasma volume. Hanel et al (1997) showed that the reduced DLco after exercise was related to decreased pulmonary blood volume and a redistribution of central blood flow, as indicated by the measure of atrial natriuretic factor (ANF). The prior cycling segment may thus decrease DLco because of both reduced plasma volume and higher blood volume in the legs that is then shifted to the chest during the subsequent run (Hue et al 2001a, b, c).…”

Early subclinical increase in pulmonary water content in athletes performing sustained heavy exercise at sea level: ultrasound lung comet-tail evidence

“…Interstitial pulmonary edema has been documented in endurance athletes performing heavy sea level exercise, using imaging techniques such as chest X-ray, magnetic resonance, computed tomography, and scintigraphy (17,36,56). Previous authors measured noninvasively the postexercise extracellular thoracic fluid volume using thoracic impedance monitoring (16). However, this method does not allow visualizing the seat of the water content in the chest.…”