Submitted on March 20, 2009
Revised on June 11, 2009
Accepted on June 12, 2009
BRONCHODILATOR EFFECTS OF EXERCISE HYPERPNEA AND ALBUTEROL IN MILD-TO-MODERATE ASTHMA
Manlio Milanese1, Riccardo Saporiti2, Stefano Bartolini3, Riccardo Giovanni Pellegrino4, Michele Pierangelo Baroffio5, Vito Brusasco3, and Emanuele Crimi3*
1 Ospedale S. Corona
2 University of Genoa, 16132 Genova
3 University of Genoa
4 Centro di Fisiopatologia Respiratoria e dello Studio della Dispnea
5 Universit di Genova
* To whom correspondence should be addressed. E-mail: emanuele.crimi{at}unige.it.
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 µg of albuterol but about 60% of the maximal bronchodilatation obtainable with 1,500 µg 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 µg) 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.
