Inhaled Albuterol does Not Protect Against Ozone Toxicity in Nonasthmatic Athletes

Abstract

We evaluated the acute prophylactic efficacy of albuterol aerosol in protecting nonasthmatic athletes from the untoward effects of 0.21 ppm ozone (O₃) on symptoms, pulmonary function, exercise performance, and post-exposure histamine bronchoprovocation. Fifteen trained competitive cyclists participated in a randomized crossover study consisting of double-blinded inhalations of albuterol (180 μg) and placebo approximately 30 min prior to heavy continuous exercise (minute ventilation, [V_E] ≥ 80 L/min) for 60 min, followed by a maximal sprint (peak V_E > 140 L/min) until exhaustion. Each subject was exposed randomly to either 0.21 ppm O₃ or filtered air (FA) during the four single-blinded exposure sessions. Albuterol pretreatment resulted in modest but significant bronchodilation as compared to placebo. However, albuterol did not prevent O₃-induced respiratory symptoms, decrements in forced vital capacity (FVC), forced expired volume in one second (FEV_1.0), and maximum midexpiratory flow rate (FEF_25–75%), and positive histamine challenges as compared to that with placebo/O₃. There were no statistically significant differences in the metabolic data or ride times across all drugs and exposures, although the peak V_E was significantly lower with O₃ than FA (142.3 vs. 150.7 L/min, respectively) regardless of drug. The results indicate that acute pretreatment with inhaled albuterol is unable to prevent or ameliorate O₃-induced symptoms and alterations in pulmonary function and exercise performance. The contribution of beta-adrenergic mechanisms in the acute airway responses to O₃ appears to be minimal.