Document Detail


Effect of high and low glycaemic index recovery diets on intramuscular lipid oxidation during aerobic exercise.
MedLine Citation:
PMID:  17697427     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Intramyocellular lipid (IMCL) and plasma NEFA are important skeletal muscle fuel sources. By raising blood insulin concentrations, carbohydrate ingestion inhibits lypolysis and reduces circulating NEFA. We hypothesised that differences in the postprandial glycaemic and insulin response to carbohydrates (i.e. glycaemic index; GI) could alter NEFA availability and IMCL use during subsequent exercise. Endurance-trained individuals (n 7) cycled for 90 min at 70 % V O2peak and then consumed either high GI (HGI) or low GI (LGI) meals over the following 12 h. The following day after an overnight fast, the 90 min cycle was repeated. IMCL content of the vastus lateralis was quantified using magnetic resonance spectroscopy before and after exercise. Blood samples were collected at 15 min intervals throughout exercise and analysed for NEFA, glycerol, glucose, insulin, and lactate. Substrate oxidation was calculated from expired air samples. The 90 min cycle resulted in >2-fold greater reduction in IMCL in the HGI trial (3.5 (sem 1.0) mm/kg wet weight) than the LGI trial (1.6 (sem 0.3) mm/kg wet weight, P < 0.05). During exercise, NEFA availability was reduced in the HGI trial compared to the LGI trial (area under curve 2.36 (sem 0.14) mEq/l per h v. 3.14 (sem 0.28) mEq/l per h, P < 0.05 respectively). No other differences were significant. The findings suggest that HGI carbohydrates reduce NEFA availability during exercise and increase reliance on IMCL as a substrate source during moderate intensity exercise.
Authors:
Michael I Trenell; Emma Stevenson; Karola Stockmann; Jennie Brand-Miller
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-08-15
Journal Detail:
Title:  The British journal of nutrition     Volume:  99     ISSN:  0007-1145     ISO Abbreviation:  Br. J. Nutr.     Publication Date:  2008 Feb 
Date Detail:
Created Date:  2008-01-10     Completed Date:  2008-03-11     Revised Date:  2014-02-19    
Medline Journal Info:
Nlm Unique ID:  0372547     Medline TA:  Br J Nutr     Country:  England    
Other Details:
Languages:  eng     Pagination:  326-32     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Adult
Bicycling / physiology*
Blood Glucose / metabolism
Diet*
Fatty Acids, Nonesterified / blood
Glycemic Index*
Glycerol / blood
Humans
Insulin / blood
Lactic Acid / blood
Lipid Metabolism / physiology*
Magnetic Resonance Spectroscopy / methods
Male
Muscle, Skeletal / metabolism*
Oxidation-Reduction
Grant Support
ID/Acronym/Agency:
MC_G0802536//Medical Research Council
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Fatty Acids, Nonesterified; 0/Insulin; 33X04XA5AT/Lactic Acid; PDC6A3C0OX/Glycerol

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


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