title: Effect of preexercise glycemic-index meal on running when CHO-electrolyte solution is consumed during exercise.
abstract: OBJECTIVE
  This study examined the effect of consuming carbohydrate- (CHO) electrolyte solution on running performance after different-glycemic-index (GI) meals.
  
  
  METHODS
  Nine men completed 3 trials in a randomized counterbalanced order, with trials separated by at least 7 days. Two hours before the run after an overnight fast, each participant consumed a high-GI (GI = 83) or low-GI (GI = 36) CHO meal or low-energy sugar-free Jell-O (GI = 0, control). The 2 isocaloric GI meals provided 1.5 g available CHO/kg body mass. During each trial, 2 ml/kg body mass of a 6.6% CHO-electrolyte solution was provided immediately before exercise and every 2.5 km after the start of running. Each trial consisted of a 21-km performance run on a level treadmill. The participants were required to run at 70% VO2max during the first 5 km of the run. They then completed the remaining 16 km as fast as possible.
  
  
  RESULTS
  There was no difference in the time to complete the 21-km run (high-GI vs. low-GI vs. control: 91.1 +/- 2.0 vs. 91.8 +/- 2.2 vs. 92.9 +/- 2.0 min, n.s.). There were no differences in total CHO and fat oxidation throughout the trials, despite differences in preexercise blood glucose, serum insulin, and serum free-fatty-acid concentrations.
  
  
  CONCLUSIONS
  When a CHO-electrolyte solution is consumed during a 21-km run, the GI of the preexercise CHO meal makes no difference in running performance.
authors: Department of Sports Science, Chinese University of Hong Kong, Shatin, Hong Kong.
authors: Stephen H S
authors: SH
authors: Wong
authors: Oi Won
authors: OW
authors: Chan
authors: Ya Jun
authors: YJ
authors: Chen
authors: Heng Long
authors: HL
authors: Hu
authors: Chin Wan
authors: CW
authors: Lam
authors: Pak Kwong
authors: PK
authors: Chung
mesh_terms: D019540:Area Under Curve; D001786:Blood Glucose / Q000378:metabolism; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage* / Q000145:classification / Q000378:metabolism; D004573:Electrolytes / Q000008:administration & dosage* / Q000378:metabolism; D038321:Glycemic Index; D006801:Humans; D007328:Insulin / Q000097:blood; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology*; D012420:Running / Q000502:physiology*; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004573:Electrolytes; D007328:Insulin; D019344:Lactic Acid