Exercise-induced bronchodilation in natural and induced asthma: effects on ventilatory response and performance.
We studied whether bronchodilatation occurs with exercise during the late asthmatic reaction (LAR) to allergen (group 1, n = 13) or natural asthma (NA; group 2, n = 8) and whether this is sufficient to preserve maximum ventilation (VE(max)), oxygen consumption (VO(2 max)), and exercise performance (W(max)). In group 1, partial forced expiratory flow at 30% of resting forced vital capacity increased during exercise, both at control and LAR. W(max) was slightly reduced at LAR, whereas VE(max), tidal volume, breathing frequency, and VO(2 max) were preserved. Functional residual capacity and end-inspiratory lung volume were significantly larger at LAR than at control. In group 2, partial forced expiratory flow at 30% of resting forced vital capacity increased greatly with exercise during NA but did not attain control values after appropriate therapy. Compared with control, W(max) was slightly less during NA, whereas VO(2 max) and VE(max) were similar. Functional residual capacity, but not end-inspiratory lung volume at maximum load, was significantly greater than at control, whereas tidal volume decreased and breathing frequency increased. In conclusion, remarkable exercise bronchodilation occurs during either LAR or NA and allows VE(max) and VO(2 max) to be preserved with small changes in breathing pattern and a slight reduction in W(max).
Crimi
Emanuele
E
Dipartimenti di Medicina Interna e di Scienze Motorie e Riabilitative, Università di Genova, 16132 Genova, Italy.
Pellegrino
Riccardo
R
Smeraldi
Attilio
A
Brusasco
Vito
V
D000328:Adult; D001249:Asthma / Q000209:etiology* / Q000503:physiopathology*; D001980:Bronchi / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D005540:Forced Expiratory Flow Rates; D005652:Functional Residual Capacity; D006801:Humans; D006967:Hypersensitivity / Q000150:complications*; D001239:Inhalation; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D012119:Respiration; D013990:Tidal Volume; D014797:Vital Capacity