Airway obstruction (AO) in exercise-induced asthma (EIA) is considered a postexercise phenomenon. However, many with EIA complain of respiratory distress during exercise. We evaluated AO in six asthmatic subjects during a short (SX = 6 min) and a long (LX = 20 min) exercise session. We measured peak expiratory flow (PEF) rate, forced expiratory volume in one second (FEV1), and forced expiratory flow at 50% of vital capacity (V̇max50) and calculated expiratory and inspiratory pulmonary resistance (RLe and RLi). Rated perceived exertion (RPE) was evaluated as a measure of dyspnea. All three indices of airflow significantly decreased following SX and LX, but RLi and file increased. During SX, PEF, FEV1, and V̇max50 did not decrease, but RLi decreased. During IX, PEF, FEV1, and V̇max50 decreased (20.0, 26.0, and 17.7%, respectively), whereas RLi and RLe significantly increased (74.0 and 53.0%). Rated perceived exertion correlated highly with RLi during exercise (r = 0.95). In summary, there was little or no AO during 5X but a frank AO during LX in asthmatic subjects. We conclude that AO occurs during LX and that the manifestation of dyspnea is associated with AO during exercise, as well as in recovery.
|Original language||English (US)|
|Number of pages||8|
|Journal||American Journal of Respiratory and Critical Care Medicine|
|State||Published - Jul 1995|
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Critical Care and Intensive Care Medicine