title: Influence of a carbohydrate-electrolyte solution ingested during running on muscle glycogen utilisation in fed humans.
abstract: This study investigated whether the ingestion of a carbohydrate-electrolyte solution during running would influence muscle glycogen utilisation in subjects who had consumed a carbohydrate meal 3 hours before exercise. Eight men completed two 60-min treadmill runs at 70% VO(2)max. Before each run they consumed a carbohydrate meal (183 +/- 7 g) 3 hours before exercise and either 1) a carbohydrate-electrolyte solution during the run (46 +/- 1 g) (M+C), or 2) water during the run (M + W). Biopsy samples were obtained from the vastus lateralis muscle at rest and after 60 min of running. Serum insulin concentrations were higher (p < 0.01) in both trials at the start of exercise compared with fasting values, whereas blood glucose concentrations were higher (p < 0.01) after 60 min of running in the M+C trial. Pre-exercise muscle glycogen concentrations were similar in both trials (M+C: 321.9 +/- 27.2 vs M+W: 338.8 +/- 32.8 mmol x kg x dry weight (-1) [dw]; NS). There was no difference in the amount of glycogen used during exercise (M+C: 96.1 +/- 22.1 vs M+W: 77.9 +/- 11.7 mmol x kg x dw (-1); NS). In conclusion, a carbohydrate-electrolyte solution ingested during treadmill running at 70 % VO(2)max does not influence muscle glycogen use during the first hour of exercise when a carbohydrate meal is consumed 3 hours before exercise.
authors.affiliation: Human Muscle Metabolism Research Group, Department of Physical Education, Sports Science and Recreation Management, Loughborough University, Loughborough, UK.
authors.forename: C
authors.initials: C
authors.lastname: Chryssanthopoulos
authors.forename: C
authors.initials: C
authors.lastname: Williams
authors.forename: A
authors.initials: A
authors.lastname: Nowitz
mesh_terms: D000328:Adult; D001628:Beverages; D001786:Blood Glucose / Q000378:metabolism; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004326:Drinking / Q000502:physiology; D004573:Electrolytes / Q000008:administration & dosage*; D005215:Fasting / Q000502:physiology; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006003:Glycogen / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000097:blood; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D012420:Running / Q000502:physiology*
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004573:Electrolytes; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D019344:Lactic Acid; D006003:Glycogen