Effect of an inhaled short-acting Beta2-agonist on the cardiorespiratory response to exercise in individuals with exercise-induced asthma

Abstract

The aim of this study was to examine the effect of an inhaled short-acting beta2-agonist, on both pulmonary function and heart rate, with the use of an exercise challenge test. Eight physically active individuals (age [mean age  s] 20.3  1.5 years; height, 165.6  5.0 cm; body mass, 67.4  19.0 kg) with physician-diagnosed asthma were tested under 2 experimental conditions: 1) with inhaler (200 µg of salbutamol); and 2) without inhaler. Following each experimental condition, participants completed an exercise challenge test which consisted of 8 minutes running on a motorised treadmill, at an intensity of 85-90% of maximum heart rate. Spirometry was used to assess pulmonary function pre-exercise and at 3, 5, 10, 15, 20 and 30 min post-exercise. Heart rate was measured pre-exercise, during exercise and at 20 min post-exercise. Results showed that when the short-acting beta2-agonist was inhaled, there was a significant increase (P<0.05) in mean pulmonary function values; forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and the percentage of the forced vital capacity expelled in the first second of expiration (FEV1/FVC ratio). Of the 8 participants, in the without inhaler condition, 4 were accepted as meeting the >10% fall in FEV1 criteria which is used in the diagnosis of exercise-induced asthma. In the with inhaler condition, only 1 participant met this criteria. No significant differences were identified in heart rate between the 2 experimental conditions. The results from this study conclude that salbutamol, a short-acting beta2-agonist, can prevent exercise-induced asthma by producing bronchodilation of the airways. Additionally, results from the study identified that salbutamol had no adverse effect on heart rate.