查看文章

The blood-gas barrier must be very thin to allow gas exchange and it is therefore subjected to high mechanical stresses when the capillary pressure rises. In some animals, such as the thoroughbred race-horse during intense exercise, the stresses are so large that the capillaries fail and bleeding occurs. We tested the hypothesis that, in elite human athletes, the high capillary pressure that occurs during severe exercise alters the structure and function of the blood-gas barrier. We performed bronchoalveolar lavage (BAL) in six healthy athletes, who had a history suggestive of lung bleeding, 1 h after a 7-min cycling race simulation and four normal sedentary control subjects who did not exercise before BAL. The athletes had higher (p < 0.05) concentrations of red blood cells (0.51 x 10(5) versus 0.01 x 10(5).ml-1), total protein (128.0 versus 94.1 micrograms/ml), albumin (65.6 versus 53.0 micrograms/ml), and …