title: Acute effects of caffeine on heart rate variability in habitual caffeine consumers.
abstract: During the last years, heart rate variability (HRV) has become a promising risk factor for cardiovascular events. However, the effect of caffeine on HRV in habitual caffeine consumers has barely been investigated. Therefore, we treated 30 male habitual caffeine users in a randomized double-blinded crossover study design with either placebo, 100 or 200 mg caffeine orally and determined parameters of HRV under resting conditions and metronomic breathing. As result, we could not detect significant differences in HRV parameters up to 90 min after drug ingestion. We conclude that modest amounts of caffeine do not reveal negative nor positive effects on HRV within the first 90 min after drug ingestion in young and healthy habitual caffeine consumers. However, further research is necessary to determine the effects of caffeine on HRV in habitual caffeine users, healthy as well as suffering from diabetes, hypertension and postmyocardial infarction.
authors.affiliation: Department for Cellular and Molecular Physiology, University Erlangen-Nürnberg, Erlangen, Germany. robert.rauh@gmx.de
authors.forename: Robert
authors.initials: R
authors.lastname: Rauh
authors.forename: Michaela
authors.initials: M
authors.lastname: Burkert
authors.forename: Martin
authors.initials: M
authors.lastname: Siepmann
authors.forename: Michael
authors.initials: M
authors.lastname: Mueck-Weymann
mesh_terms: D000328:Adult; D002110:Caffeine / Q000008:administration & dosage / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000494:pharmacology*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004562:Electrocardiography; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D018709:Statistics, Nonparametric
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine