| Fuel selection and cycling endurance performance with ingestion of [13C]glucose: evidence for a carbohydrate dose response. | |
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MedLine Citation:
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PMID: 20299609 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Endurance performance and fuel selection while ingesting glucose (15, 30, and 60 g/h) was studied in 12 cyclists during a 2-h constant-load ride [approximately 77% peak O2 uptake] followed by a 20-km time trial. Total fat and carbohydrate (CHO) oxidation and oxidation of exogenous glucose, plasma glucose, glucose released from the liver, and muscle glycogen were computed using indirect respiratory calorimetry and tracer techniques. Relative to placebo (210+/-36 W), glucose ingestion increased the time trial mean power output (%improvement, 90% confidence limits: 7.4, 1.4 to 13.4 for 15 g/h; 8.3, 1.4 to 15.2 for 30 g/h; and 10.7, 1.8 to 19.6 for 60 g/h glucose ingested; effect size=0.46). With 60 g/h glucose, mean power was 2.3, 0.4 to 4.2% higher, and 3.1, 0.5 to 5.7% higher than with 30 and 15 g/h, respectively, suggesting a relationship between the dose of glucose ingested and improvements in endurance performance. Exogenous glucose oxidation increased with ingestion rate (0.17+/-0.04, 0.33+/-0.04, and 0.52+/-0.09 g/min for 15, 30, and 60 g/h glucose), but endogenous CHO oxidation was reduced only with 30 and 60 g/h due to the progressive inhibition of glucose released from the liver (probably related to higher plasma insulin concentration) with increasing ingestion rate without evidence for muscle glycogen sparing. Thus ingestion of glucose at low rates improved cycling time trial performance in a dose-dependent manner. This was associated with a small increase in CHO oxidation without any reduction in muscle glycogen utilization. |
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Authors:
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JohnEric W Smith; Jeffrey J Zachwieja; François Péronnet; Dennis H Passe; Denis Massicotte; Carole Lavoie; David D Pascoe |
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Publication Detail:
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Type: Journal Article Date: 2010-03-18 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 108 ISSN: 1522-1601 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2010 Jun |
Date Detail:
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Created Date: 2010-06-03 Completed Date: 2010-10-08 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 1520-9 Citation Subset: IM |
Affiliation:
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Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL 60074, USA. johneric.smith@gatorade.com |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Administration, Oral Adult Bicycling / physiology* Dietary Carbohydrates / administration & dosage*, metabolism* Dose-Response Relationship, Drug Glucose / administration & dosage* Humans Male Physical Endurance / drug effects, physiology* Task Performance and Analysis* |
| Chemical | |
Reg. No./Substance:
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0/Dietary Carbohydrates; 50-99-7/Glucose |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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