Hyperoxic attenuation of exercise-induced bronchospasm in asthmatics.

To investigate the mechanism of exercise-induced bronchospasm, we measured specific airway conductance before and after exercise in 7 healthy normals, 12 asthmatics with intact carotid bodies, and 5 asthmatics who had had bilateral carotid body resection. The subjects breathed either air or oxygen (randomly assigned) during cycle ergometer exercise. Post-exercise bronchodilation was the usual pattern in normals, whereas post-exercise bronchospasm occurred in all asthmatics who breathed air during exercise. Oxygen breathing during exercise markedly attenuated the post-exercise bronchospasm in t...

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