title: [Effects of cimetidine on chronotropic response to cardiopulmonary exercise testing].
abstract: OBJECTIVE
  To test the hypothesis that the administration of cimetidine will modify the chronotropic response to exercise testing through a random clinical trial.
  
  
  METHODS
  The study selected 24 eligible healthy subjects, ages between 20 and 68 years, not athletes, who agreed to undergo cardiopulmonary exercise testing after the administration of placebo and 400 mg of cimetidine twice a day for one week. The tests were performed on a treadmill using a ramp protocol and direct analysis of the expired gases. Peak, resting and anaerobic threshold heart rate were recorded.
  
  
  RESULTS
  The twenty subjects studied were equally distributed across sex with mean (+/- SD) age 43 +/- 11 years. Tests on placebo and on cimetidine presented similar duration (578 +/- 90 sec vs 603 +/- 131 sec) and similar peak oxygen uptake (35 +/- 8 ml/kg.min vs 35 +/- 8 ml/kg.min). Cimetidine administration had no significant effect on resting heart rate (75 +/- 10 bpm vs 74 +/- 8 bpm), heart rate at peak exercise (176 +/- 12 bpm vs 176 +/- 11 bpm), and on the difference between the peak and the resting heart rates--delta HR (101 +/- 14 bpm vs 101 +/- 13 bpm).
  
  
  CONCLUSIONS
  The administration of cimetidine for 7 days has no significant effect on the chronotropic response to exercise testing.
authors.affiliation: Clínica Cardiométodo, Hospital Ernesto Dornelles, UFRGS, Porto Alegre, RS.
authors.forename: Gicela Risso
authors.initials: GR
authors.lastname: Rocha
authors.forename: Ricardo
authors.initials: R
authors.lastname: Stein
authors.forename: Márcio R
authors.initials: MR
authors.lastname: Guimarães
authors.forename: Jorge Pinto
authors.initials: JP
authors.lastname: Ribeiro
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D002927:Cimetidine / Q000008:administration & dosage / Q000494:pharmacology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005080:Exercise Test / Q000187:drug effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology; D006635:Histamine H2 Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D008297:Male; D017678:Sex Distribution
chemical_list: D006635:Histamine H2 Antagonists; D002927:Cimetidine