title: Caffeine consumption decreases the response to bronchoprovocation challenge with dry gas hyperventilation.
abstract: OBJECTIVE
  To determine whether caffeine consumption affects bronchoprovocation challenge (BPC).
  
  
  METHODS
  A prospective, double-blind, placebo-controlled, randomized, crossover trial.
  
  
  METHODS
  Eleven nonsmoking men, aged 18 to 42 years, with normal baseline spirometry and evidence of exercise-induced bronchospasm.
  
  
  METHODS
  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.
authors.affiliation: Department of Medicine, Walter Reed Army Medical Center, Washington, DC 20307-5000.
authors.forename: P
authors.initials: P
authors.lastname: Duffy
authors.forename: Y Y
authors.initials: YY
authors.lastname: Phillips
mesh_terms: D000293:Adolescent; D000328:Adult; D001250:Asthma, Exercise-Induced / Q000097:blood / Q000503:physiopathology; D001985:Bronchial Provocation Tests / Q000379:methods; D016084:Bronchoconstriction / Q000187:drug effects*; D002110:Caffeine / Q000097:blood / Q000494:pharmacology*; D004311:Double-Blind Method; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D006813:Humidity; D006985:Hyperventilation / Q000503:physiopathology*; D008297:Male; D011446:Prospective Studies; D013806:Theophylline / Q000097:blood; D014797:Vital Capacity
chemical_list: D002110:Caffeine; D013806:Theophylline