Abstract

The main aim of this study was to evaluate the comparative and additive effects of caffeine and albuterol (short-acting β2-agonist) on the severity of EIB. Ten asthmatic subjects with EIB (exercise-induced bronchoconstriction) participated in a randomized, double-blind, double-dummy crossover study. One hour before an exercise challenge, each subject was given 0, 3, 6, or 9 mg/kg of caffeine or placebo mixed in a flavored sugar drink. Fifteen minutes before the exercise bout, an inhaler containing either albuterol (180 μg) or placebo was administered to each subject. Pulmonary function tests were conducted pre- and post-exercise. Caffeine at a dose of 6 and 9 mg/kg significantly reduced (p<0.05) the mean maximum % fall in post-exercise FEV1 to −9.0 +/- 9.2% and −6.8 +/- 6.5% respectively compared to the double-placebo (−14.3 +/- 11.1%) and baseline (−18.4 +/- 7.2%). There was no significant difference (p>0.05) in the post-exercise % fall in FEV1 between albuterol (plus caffeine placebo) (−4.0 +/- 5.2%) and the 9 mg/kg dose of caffeine (−6.8 +/- 6.5%). Interestingly, there was no significant difference (p>0.05) in the post-exercise % fall in FEV1 between albuterol (plus caffeine placebo) (−4.0 +/- 5.2%) and albuterol with 3, 6 or 9 mg/kg of caffeine (−4.4 +/- 3.8, −6.8 +/- 5.6, −4.4 +/- 6.0% respectively). Similar changes were observed for the post-exercise % fall in FVC, FEF25-75% and PEF. These data indicate that moderate (6 mg/kg) to high doses (9 mg/kg) of caffeine provide a significant protective effect against EIB. It is feasible that the negative effects of daily use of short-acting β2-agonists by asthmatic athletes could be reduced simply by increasing caffeine consumption prior to exercise. Verf.-Referat