Effects on ventilatory response and performance: Exercise-induced bronchodilation in natural and induced asthma

Crimi, Emanuele, Riccardo Pellegrino, Attilio Smeraldi, and Vito Brusasco. Exercise-induced bronchodilation in natural and induced asthma: effects on ventilatory response
and performance. J Appl Physiol 92: 2353–2360, 2002. First published February 22, 2002; 10.1152/japplphysiol.01248.2001.—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(V˙ Emax), oxygen consumption (V˙ O2 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 V˙ Emax, tidal volume, breathing frequency, and
V˙ O2 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 V˙ O2 max and V˙ Emax 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 V˙Emax and V˙ O2 max to be preserved with small changes in breathing pattern and a slight reduction in W˙ max. incremental exercise; natural asthma; late asthmatic reaction;deep inhalation; breathing pattern....

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