title: Supplementation with a low-dose of octopamine does not influence endurance cycling performance in recreationally active men.
abstract: OBJECTIVE
  The aim of this study was to examine the influence of octopamine supplementation on endurance performance and exercise metabolism.
  
  
  METHODS
  Double-blind cross-over study.
  
  
  METHODS
  Ten healthy, recreationally active men (Mean±SD; age: 24±2 years; body mass: 78.4±8.7kg; VO2peak: 50.5±6.8 mLkg-1min-1) completed one VO2peaktest, one familiarisation trial and two experimental trials. After an overnight fast, participants ingested either a placebo or 150mg of octopamine 60min prior to exercise. Trials consisted of 30min of cycle exercise at 55% peak power output, followed by a 30min performance task whereby participants completed as much work (kJ) as possible.
  
  
  RESULTS
  Performance was similar between the experimental trials (placebo: 352.8±39kJ; octopamine: 350.9±38.3kJ; Cohen's d effect size=0.05; p=0.380). Substrate oxidation and circulating concentrations of free fatty acids, prolactin and cortisol were similar between trial conditions (all p>0.05). There were also no differences across trials for heart rate or perceived exertion during exercise (both p>0.05).
  
  
  CONCLUSIONS
  Acute supplementation with a low dose of octopamine did not influence endurance cycle performance, substrate oxidation or circulating hormonal concentrations, which could be due to the low serum octopamine concentrations observed. Future studies should investigate the influence of larger doses of octopamine in recreationally active and well-trained individuals during prolonged exercise in temperate and high ambient conditions.
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, UK. Electronic address: r.e.beaumont@lboro.ac.uk.
authors.forename: Ross E
authors.initials: RE
authors.lastname: Beaumont
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, UK.
authors.forename: Philip
authors.initials: P
authors.lastname: Cordery
authors.affiliation: School of Sport, Exercise and Health Sciences, Loughborough University, UK.
authors.forename: Lewis J
authors.initials: LJ
authors.lastname: James
authors.affiliation: Department of Human Physiology and Sports Medicine, Vrije Universiteit Brussel, Belgium.
authors.forename: Phillip
authors.initials: P
authors.lastname: Watson
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D004734:Energy Metabolism / Q000187:drug effects; D015444:Exercise / Q000502:physiology*; D017079:Exercise Tolerance / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D009655:Octopamine / Q000008:administration & dosage* / Q000097:blood / Q000494:pharmacology; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000187:drug effects; D058573:Performance-Enhancing Substances; D011388:Prolactin / Q000097:blood; D011897:Random Allocation; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000008:administration & dosage*; D055815:Young Adult; D000095383:Trace Amine-Associated Receptors
chemical_list: D006854:Hydrocortisone; D009655:Octopamine; D058573:Performance-Enhancing Substances; D011388:Prolactin; D043562:Receptors, G-Protein-Coupled; D014662:Vasoconstrictor Agents; D000095383:Trace Amine-Associated Receptors
keywords: Exercise; Fatigue; Stimulants; Substrate oxidation; Supplements