Maximal airway narrowing on the dose-response curve to methacholine is increased after exercise-induced bronchoconstriction.
The changes in airway responsiveness between before and after exercise in asthma are not well defined. We investigated the effect of exercise on PC20 (bronchial sensitivity) and maximal airway narrowing (MAN) on the dose-response curve to methacholine in 56 mildly asthmatic children. High-dose methacholine inhalation tests were performed before and 7 hr after exercise challenge. Methacholine PC20 was not changed by exercise, irrespective of exercise-induced bronchoconstriction (EIB). However, the subjects with (+)EIB displayed increased MAN after exercise, whereas those with (+/-)EIB or (-)EIB did not. The results showed that EIB may be followed by increased MAN but not by the change of bronchial sensitivity.
Koh
Y Y
YY
Department of Pediatrics, Seoul National University College of Medicine, Korea.
Lim
H S
HS
Min
K U
KU
Kim
Y Y
YY
D000280:Administration, Inhalation; D001250:Asthma, Exercise-Induced / Q000175:diagnosis* / Q000503:physiopathology*; D001980:Bronchi / Q000187:drug effects / Q000503:physiopathology*; D016084:Bronchoconstriction / Q000187:drug effects*; D002648:Child; D004305:Dose-Response Relationship, Drug; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008297:Male; D016210:Methacholine Chloride
D016210:Methacholine Chloride