Predictors of exercise-induced bronchoconstriction in subjects with mild asthma

Abstract Background Physical effort is capable of triggering airway obstruction in asthmatics, the so-called exercise-induced bronchoconstriction asthma (EIBa). This study was performed subjects with mild persistent asthma, aiming to find predictors for developing EIBa. Methods In 20 measurements baseline functional respiratory parameters and airways responsiveness by a methacholine challenge were obtained on first day. A maximal, symptom-limited incremental cardiopulmonary exercise test (CPExT) day after, subsequent, repeated maneuvers maximal full forced expiration monitor FEV 1 change at 1,3,5,7,10 15 min after end exercise. Results 19 completed two-days protocol. No both rest during useful predict EIBa stopping asthmatics EIBa, mean Inspiratory Capacity (IC) did not increase increasing ventilatory requirements CPExT because 6 them (50%) displayed dynamic pulmonary hyperinflation (DH), as documented their progressive end-expiratory lung volume. subgroup, showing earlier post-exercise fall, had significantly lower expiratory flow between 25% 75% vital capacity (FEF 25-75% ) (p < 0.05) higher responsiveness, expressed PD compared other Conclusions seem asthmatics. However, those subgroup developed DH exercise, this associated reduced rates volumes hyperresponsiveness, suggesting prominent small impairment.