Reduction of body stores of carbohydrate and blood glucose is related to the perception of fatigue and the inability to maintain high-quality performance. This has been clearly shown with aerobic, endurance events of moderate intensity of over 90 min duration. Carbohydrate intake may also have relevance for athletes involved in short, high-intensity events, especially if body weight control is an issue. Prevention of carbohydrate depletion begins with a high-carbohydrate training diet of about 60-70% carbohydrate. If possible, carbohydrate beverages should be consumed during the event at the rate of 30-70 g/hr to reduce the chance of body carbohydrate depletion. Finally, replacement of body carbohydrate stores can be achieved most rapidly if 40-60 g of carbohydrate is consumed as soon as possible after the exercise and at repeating 1-hr intervals for at least 5 hr after the event.
Janet Walberg-Rankin is with the Laboratory for Health and Exercise Sciences, Department of Human Nutrition and Foods, Virginia Tech, Blacksburg, VA 24061-0351.