Alveolar epithelial integrity in athletes with exercise-induced hypoxemia

Michael R. Edwards, Garth S. Hunte, Allan S. Belzberg, A. William Sheel, Dan F. Worsley, Donald C. McKenzie
2000 Journal of applied physiology  
epithelial integrity in athletes with exercise-induced hypoxemia. J Appl Physiol 89: [1537][1538][1539][1540][1541][1542] 2000.-The effect of incremental exercise to exhaustion on the change in pulmonary clearance rate (k) of aerosolized 99m Tc-labeled diethylenetriaminepentaacetic acid ( 99m Tc-DTPA) and the relationship between k and arterial PO 2 (Pa O 2 ) during heavy work were investigated. Ten male cyclists (age ϭ 25 Ϯ 2 yr, height ϭ 180.9 Ϯ 4.0 cm, mass ϭ 80.1 Ϯ 9.5 kg, maximal O 2
more » ... ϭ 5.25 Ϯ 0.35 l/min, mean Ϯ SD) completed a pulmonary clearance test shortly (39 Ϯ 8 min) after a maximal O 2 uptake test. Resting pulmonary clearance was completed Ն24 h before or after the exercise test. Arterial blood was sampled at rest and at 1-min intervals during exercise. Minimum Pa O 2 values and maximum alveolar-arterial PO 2 difference ranged from 73 to 92 Torr and from 30 to 55 Torr, respectively. No significant difference between resting k and postexercise k for the total lung (0.55 Ϯ 0.20 vs. 0.57 Ϯ 0.17 %/min, P Ͼ 0.05) was observed. Pearson product-moment correlation indicated no significant linear relationship between change in k for the total lung and minimum Pa O 2 (r ϭ Ϫ0.26, P Ͼ 0.05). These results indicate that, averaged over subjects, pulmonary clearance of 99m Tc-DTPA after incremental maximal exercise to exhaustion in highly trained male cyclists is unchanged, although the sampling time may have eliminated a transient effect. Lack of a linear relationship between k and minimum Pa O 2 during exercise suggests that exercise-induced hypoxemia occurs despite maintenance of alveolar epithelial integrity. pulmonary clearance of technetium-99m-diethylenetriaminepentaacetic acid; alveolar epithelium; gas exchange EXERCISE-INDUCED HYPOXEMIA (EIH), defined as the inability to maintain arterial PO 2 (Pa O 2 ) and arterial oxyhemoglobin saturation (Sa O 2 ) during exercise, occurs in some high-aerobic-power athletes and is associated with a widened alveolar-arterial PO 2 gradient (A-aPO 2 ) (3, 4, 12, 29). The precise etiology of EIH and the widened A-aPO 2 remains unclear but is likely the result of, or an interaction among, relative alveolar hypoventilation, ventila-
doi:10.1152/jappl.2000.89.4.1537 pmid:11007593 fatcat:oiohjur4uvdaloqgdmjbujv3ea