Document Detail

Duathlon performance unaltered by short-term changes in dietary fat and carbohydrates.
MedLine Citation:
PMID:  19403953     Owner:  NLM     Status:  MEDLINE    
PURPOSE: This study investigated the effects of short-term dietary changes on metabolism and duathlon performance. METHODS: Eleven men underwent a high-fat (HF; >65% fat from energy) or a high-carbohydrate (CHO; HC) diet (>60% CHO from energy). Energy intake was individualized, and commercially available foods were prepared and packaged for each participant 48 hr before they completed a laboratory-based duathlon (5-km run, 30 km cycling, and 10-km run). Blood samples were obtained before, immediately after, and 1 and 2 hr after the duathlon for determination of glucose, insulin, and glucagon. Oxygen consumption, ratings of perceived exertion (RPE), and respiratory-exchange ratio were assessed, and fat and CHO oxidation were estimated before, during, and after the duathlon. RESULTS: Dietary records indicated a significant difference in fat content ingested before the duathlons (p < .05). Time to complete the duathlon did not differ between the HC- and the HF-diet trials. CHO-oxidation rate was higher during the HC-diet trial than during the HF-diet trial (p = .006). Fat-oxidation rates were higher in the HF-diet trial than in the HC-diet trial (p = .001). No differences in RPE were found between dietary trials. Blood glucose concentration was higher immediately after the duathlon in the HC-diet trial than in the HF-diet trial and remained higher 1 and 2 hr after the duathlon (p < .05). CONCLUSION: Duathlon performance was not altered by short-term changes in dietary fat or CHO composition despite higher blood glucose concentrations under the HC condition.
Jose Moncada-Jimenez; Eric P Plaisance; Michael L Mestek; Lance Ratcliff; Felipe Araya-Ramirez; James K Taylor; Peter W Grandjean; Luis F Aragonvargas
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Publication Detail:
Type:  Journal Article; 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:  47-60     Citation Subset:  IM    
School of Physical Education and Sports, University of Costa Rica.
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MeSH Terms
Adaptation, Physiological / physiology
Area Under Curve
Blood Glucose / metabolism
Cross-Over Studies
Dietary Carbohydrates / administration & dosage*
Dietary Fats / administration & dosage*
Energy Intake / physiology
Energy Metabolism / drug effects*,  physiology
Glucagon / metabolism
Insulin / blood
Oxygen Consumption / physiology
Physical Endurance / drug effects*,  physiology*
Task Performance and Analysis
Young Adult
Reg. No./Substance:
0/Blood Glucose; 0/Dietary Carbohydrates; 0/Dietary Fats; 11061-68-0/Insulin; 9007-92-5/Glucagon

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