Caffeine consumption decreases the response to bronchoprovocation challenge with dry gas hyperventilation.

OBJECTIVE To determine whether caffeine consumption affects bronchoprovocation challenge (BPC). DESIGN A prospective, double-blind, placebo-controlled, randomized, crossover trial. PATIENTS Eleven nonsmoking men, aged 18 to 42 years, with normal baseline spirometry and evidence of exercise-induced bronchospasm. INTERVENTION On three separate test days, each individual received, in random order, either placebo, 5 mg/kg caffeine, or 10 mg/kg caffeine, and then underwent BPC with eucapnic voluntary hyperventilation (EVH). RESULTS Caffeine (10 mg/kg) significantly reduced bronchoconstriction compared to placebo (p = 0.02). The reduction in bronchoconstriction correlated with the serum level of caffeine (p = 0.014). CONCLUSIONS Caffeine decreases bronchoconstriction due to EVH. Caffeine should be eliminated from diet prior to BPC.