Comparison between carbohydrate feedings before and during exercise on running performance during a 30-km treadmill time trial.
The purpose of this study was to compare the effects of a carbohydrate-electrolyte solution, ingested during exercise, with the effects of a preexercise carbohydrate meal on endurance running performance. Ten endurance-trained males completed two 30-km treadmill runs. In one trial subjects consumed a placebo solution 4 hr before exercise and a carbohydrate-electrolyte solution immediately before exercise and every 5 km (C). In the other trial, subjects consumed a 4-hr preexercise high-carbohydrate meal and water immediately before exercise and every 5 km (M). Performance times were identical for M and C, and there was no difference in the self-selected speeds. Oxygen uptake, heart rates, perceived rate of exertion, and respiratory exchange ratios were also similar. However, blood glucose concentration was higher in C during the first 20 km of the 30-km run. In M, blood glucose concentration was maintained above 4.5 mmol.L-1 throughout exercise. Thus, the two conditions produced the same 30-km treadmill running performance time.
Chryssanthopoulos
C
C
Department of Physical Education, Sports Science and Recreation Management, Loughborough University, Leicestershire, UK.
Williams
C
C
Wilson
W
W
Asher
L
L
Hearne
L
L
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000494:pharmacology*; D004573:Electrolytes / Q000008:administration & dosage / Q000494:pharmacology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D009752:Nutritional Status; D010807:Physical Endurance / Q000502:physiology*; D012119:Respiration / Q000502:physiology; D012420:Running / Q000502:physiology*; D016037:Single-Blind Method; D013997:Time Factors
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004573:Electrolytes