Document Detail

Improved cycling time-trial performance after ingestion of a caffeine energy drink.
MedLine Citation:
PMID:  19403954     Owner:  NLM     Status:  MEDLINE    
CONTEXT: Not all athletic competitions lend themselves to supplementation during the actual event, underscoring the importance of preexercise supplementation to extend endurance and improve exercise performance. Energy drinks are composed of ingredients that have been found to increase endurance and improve physical performance. PURPOSE: The purpose of the study was to investigate the effects of a commercially available energy drink, ingested before exercise, on endurance performance. METHODS: The study was a double-blind, randomized, crossover design. After a 12-hr fast, 6 male and 6 female trained cyclists (mean age 27.3 +/- 1.7 yr, mass 68.9 +/- 3.2 kg, and VO2 54.9 +/- 2.3 ml x kg-1 x min-1) consumed 500 ml of either flavored placebo or Red Bull Energy Drink (ED; 2.0 g taurine, 1.2 g glucuronolactone, 160 mg caffeine, 54 g carbohydrate, 40 mg niacin, 10 mg pantothenic acid, 10 mg vitamin B6, and 10 microg vitamin B12) 40 min before a simulated cycling time trial. Performance was measured as time to complete a standardized amount of work equal to 1 hr of cycling at 70% Wmax. RESULTS: Performance improved with ED compared with placebo (3,690 +/- 64 s vs. 3,874 +/- 93 s, p < .01), but there was no difference in rating of perceived exertion between treatments. b-Endorphin levels increased during exercise, with the increase for ED approaching significance over placebo (p = .10). Substrate utilization, as measured by open-circuit spirometry, did not differ between treatments. CONCLUSION: These results demonstrate that consuming a commercially available ED before exercise can improve endurance performance and that this improvement might be in part the result of increased effort without a concomitant increase in perceived exertion.
John L Ivy; Lynne Kammer; Zhenping Ding; Bei Wang; Jeffrey R Bernard; Yi-Hung Liao; Jungyun Hwang
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  International journal of sport nutrition and exercise metabolism     Volume:  19     ISSN:  1526-484X     ISO Abbreviation:  Int J Sport Nutr Exerc Metab     Publication Date:  2009 Feb 
Date Detail:
Created Date:  2009-04-30     Completed Date:  2009-05-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100939812     Medline TA:  Int J Sport Nutr Exerc Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  61-78     Citation Subset:  IM    
Department of Kinesiology and Health Education, University of Texas, Austin, TX 78712-0360, USA.
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MeSH Terms
Area Under Curve
Basal Metabolism / drug effects,  physiology
Bicycling / physiology*
Blood Glucose / metabolism
Caffeine / administration & dosage*
Cross-Over Studies
Double-Blind Method
Lactates / metabolism
Oxygen Consumption / drug effects*,  physiology
Physical Endurance / drug effects*,  physiology
Task Performance and Analysis
Reg. No./Substance:
0/Blood Glucose; 0/Lactates; 58-08-2/Caffeine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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