Carbohydrate feedings 1 h before exercise improves cycling performance.
The effects of consuming two different amounts of liquid carbohydrate 1 h before exercise on the metabolic responses during exercise and on exercise performance were determined. Subjects consumed either 1.1 g (LC) or 2.2 g (HC) carbohydrate/kg body mass or a placebo (P). Subjects cycled at 70% of maximal oxygen consumption (VO2max) for 90 min and then underwent a performance trial. Blood glucose and insulin responses during exercise were different among the three trials. Total carbohydrate oxidation was greater for the carbohydrate trials compared with P. Time-trial performance was significantly improved by LC and HC. Despite elevated insulin concentrations at the start of and during exercise, and despite an initial drop in blood glucose, consumption of between 1.1 and 2.2 g liquid carbohydrate/kg body mass 60 min before moderately intense prolonged exercise can improve performance, presumably via enhanced carbohydrate oxidation.
Sherman
W M
WM
Exercise Physiology Laboratory, School of Health, Physical Education, and Recreation, Ohio State University, Columbus.
Peden
M C
MC
Wright
D A
DA
D000328:Adult; D001642:Bicycling; D001786:Blood Glucose / Q000032:analysis; D004040:Dietary Carbohydrates / Q000378:metabolism / Q000494:pharmacology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006339:Heart Rate; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D005082:Physical Exertion; D011659:Pulmonary Gas Exchange; D013997:Time Factors
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D005230:Fatty Acids, Nonesterified; D007328:Insulin