title: Influence of energy drinks and alcohol on post-exercise heart rate recovery and heart rate variability.
abstract: BACKGROUND
  Media have anecdotally reported that drinking energy drinks in combination with alcohol and exercise could cause sudden cardiac death. This study investigated changes in the electrocardiogram (ECG) and heart rate variability after intake of an energy drink, taken in combination with alcohol and exercise.
  
  
  METHODS
  Ten healthy volunteers (five men and five women aged 19-30) performed maximal bicycle ergometer exercise for 30 min after: (i) intake of 0.75 l of an energy drink mixed with alcohol; (ii) intake of energy drink; and, (iii) no intake of any drink. ECG was continuously recorded for analysis of heart rate variability and heart rate recovery.
  
  
  RESULTS
  No subject developed any clinically significant arrhythmias. Post-exercise recovery in heart rate and heart rate variability was slower after the subjects consumed energy drink and alcohol before exercise, than after exercise alone.
  
  
  CONCLUSIONS
  The healthy subjects developed blunted cardiac autonomic modulation after exercising when they had consumed energy drinks mixed with alcohol. Although they did not develop any significant arrhythmia, individuals predisposed to arrhythmia by congenital or other rhythm disorders could have an increased risk for malignant cardiac arrhythmia in similar situations.
authors.affiliation: Department of Biomedical Engineering & Informatics, University Hospital, Umeå, Sweden. urban.wiklund@vll.se
authors.forename: Urban
authors.initials: U
authors.lastname: Wiklund
authors.forename: Marcus
authors.initials: M
authors.lastname: Karlsson
authors.forename: Mats
authors.initials: M
authors.lastname: Oström
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Messner
mesh_terms: D000328:Adult; D000434:Alcoholic Beverages / Q000009:adverse effects*; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000503:physiopathology; D001341:Autonomic Nervous System / Q000187:drug effects*; D001628:Beverages / Q000009:adverse effects*; D004562:Electrocardiography; D004734:Energy Metabolism / Q000187:drug effects*; D000431:Ethanol / Q000009:adverse effects*; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000294:innervation*; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D020127:Recovery of Function; D018570:Risk Assessment; D013997:Time Factors; D055815:Young Adult
chemical_list: D000431:Ethanol