Milanese M, Saporiti R, Bartolini S, Pellegrino RG, Baroffio MP, Brusasco V, Crimi E
BRONCHODILATOR EFFECTS OF EXERCISE HYPERPNEA AND ALBUTEROL IN MILD-TO-MODERATE ASTHMA. [JOURNAL ARTICLE]
J Appl Physiol 2009 Jun 18.
In asthmatic subjects, either bronchodilatation or bronchoconstriction may develop during exercise. We studied two groups of asthmatic subjects with baseline mild-to-moderate airflow obstruction with the aims to 1) quantify the bronchodilator effect of incremental maximum exercise hyperpnea in comparison with inhaled albuterol, 2) to assess the impact of this effect on airway response to prolonged constant-load exercise, and 3) to evaluate if the bronchodilator effects of exercise and albuterol are additive. Changes in airway caliber were measured by changes in partial forced expiratory flow. Incremental-load exercise was associated with a bronchodilatation that was similar to that obtainable with 400 microg of albuterol but about 60% of the maximal bronchodilatation obtainable with 1,500 microg albuterol. Constant-load exercise was associated with an initial moderate bronchodilatation, which was followed by airway re-narrowing. With both exercise protocols, premedication with inhaled albuterol (400 microg) promoted sustained bronchodilatation during exercise, which was additive to that caused by exercise hyperpnea. In conclusion, our data show that exercise hyperpnea has a potent bronchodilator effect, but less that inhaled albuterol. This effect seems to contribute to delay the development of exercise-induced bronchoconstriction and is additive with that of albuterol. Key words: Exercise induced bronchoconstriction, incremental-load exercise, constant-load exercise, airway smooth muscle.
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