title: Bronchodilator effects of exercise hyperpnea and albuterol in mild-to-moderate asthma.
abstract: In asthmatic patients, either bronchodilatation or bronchoconstriction may develop during exercise. In 18 patients with mild-to-moderate asthma, we conducted two studies with the aims to 1) quantify the bronchodilator effect of hyperpnea induced by incremental-load maximum exercise compared with effects of inhaled albuterol (study 1, n=10) and 2) determine the time course of changes in airway caliber during prolonged constant-load exercise (study 2, n=8). In both studies, it was also investigated whether the bronchodilator effects of exercise hyperpnea and albuterol are additive. Changes in airway caliber were measured by changes in partial forced expiratory flow. In study 1, incremental-load exercise was associated with a bronchodilatation that was approximately 60% of the maximal bronchodilatation obtainable with 1,500 microg of albuterol. In study 2, constant-load exercise was associated with an initial moderate bronchodilatation and a late airway renarrowing. In both studies, premedication with inhaled albuterol (400 microg) promoted sustained bronchodilatation during exercise, which was additive to that caused by exercise hyperpnea. In conclusion, in mild-to-moderate asthmatic individuals, hyperpnea at peak exercise was associated with a potent yet not complete bronchodilatation. During constant-load exercise, a transient bronchodilatation was followed by airway renarrowing, suggesting prevalence of constrictor over dilator effects of hyperpnea. Finally, the bronchodilator effect of hyperpnea was additive to that of albuterol.
authors.affiliation: S.C. Pneumologia, Ospedale S. Corona, Pietra Ligure, Italy.
authors.forename: Manlio
authors.initials: M
authors.lastname: Milanese
authors.forename: Riccardo
authors.initials: R
authors.lastname: Saporiti
authors.forename: Stefano
authors.initials: S
authors.lastname: Bartolini
authors.forename: Riccardo
authors.initials: R
authors.lastname: Pellegrino
authors.forename: Michele
authors.initials: M
authors.lastname: Baroffio
authors.forename: Vito
authors.initials: V
authors.lastname: Brusasco
authors.forename: Emanuele
authors.initials: E
authors.lastname: Crimi
mesh_terms: D000222:Adaptation, Physiological; D000280:Administration, Inhalation; D000328:Adult; D000420:Albuterol / Q000008:administration & dosage*; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology; D016084:Bronchoconstriction / Q000187:drug effects*; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D015444:Exercise; D005260:Female; D005541:Forced Expiratory Volume; D005652:Functional Residual Capacity; D006801:Humans; D008297:Male; D008875:Middle Aged; D012123:Pulmonary Ventilation; D012720:Severity of Illness Index; D013997:Time Factors; D014109:Total Lung Capacity; D016896:Treatment Outcome; D014797:Vital Capacity; D055815:Young Adult
chemical_list: D001993:Bronchodilator Agents; D000420:Albuterol