Pre-exercise carbohydrate feedings and endurance performance

Six men were studied to compare the effects of pre-exercise carbohydrate feedings on endurance performance and muscle glycogen utilization during exhaustive exercise. Trials consisted of a cycling ride to exhaustion at 757. of the subjects' maximal oxygen uptake preceded by the ingestion of either fructose (FRU), glucose (GLU), or sweet placebo (CON). No differences were observed between trials for oxygen uptake, respiratory exchange ratio, heart rate, or exercise time to exhaustion. Blood glucose was elevated (PO.05). It was concluded that despite more stable blood glucose and insulin levels in FRU and CON, compared with GLU, this provided no advantage to endurance performance or muscle glycogen utilization.Thesis (M.A.