Document Detail

Effects of caffeine, fructose, and glucose ingestion on muscle glycogen utilization during exercise.
MedLine Citation:
PMID:  3431374     Owner:  NLM     Status:  MEDLINE    
Five competitive cyclists were used to determine the effects of fluid intake (16 consisting of: (i) non-nutrient control (CON); (ii) fructose (1 before exercise (FRU); (iii) caffeine (5 before exercise (CAF); (iv) glucose (1 during exercise (GLU); and (v) fructose/caffeine before and glucose during exercise (CFG) on blood glucose, free fatty acids, muscle glycogen, and other parameters. Exercise consisted of 90 min of cycling at 65 to 70% VO2max. Following exercise, blood glucose was found to be significantly (P less than 0.05) higher for CFG and GLU (117 and 109 mg%) compared to CON, CAF, and FRU (92, 89, and 86 mg%). Blood free fatty acids rose (P less than 0.05) further for CON (1,336), CAF (1,126), and FRU (1,034) over CFG (737) and GLU (714 mumol.l-1). Muscle glycogen utilization was greater (P less than 0.05) for CON (91) vs CAF (63) and GLU (62 mumol/g-1 wet muscle weight). It was concluded that GLU and CAF decrease muscle glycogen utilization, FRU is likely to cause gastric upset, and ingestion of multiple substances produces the greatest variability in muscle glycogen utilization and may provide added endurance benefits in some individuals.
M A Erickson; R J Schwarzkopf; R D McKenzie
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  19     ISSN:  0195-9131     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  1987 Dec 
Date Detail:
Created Date:  1988-03-22     Completed Date:  1988-03-22     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  579-83     Citation Subset:  IM; S    
Movement Science Laboratory, Montana State University, Bozeman 59717.
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MeSH Terms
Caffeine / pharmacology*
Fructose / pharmacology*
Glucose / pharmacology*
Glycogen / metabolism*
Muscles / metabolism*
Physical Endurance
Physical Exertion*
Reg. No./Substance:
30237-26-4/Fructose; 50-99-7/Glucose; 58-08-2/Caffeine; 9005-79-2/Glycogen

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

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