Fluid Replacement and Heat Stress, 1993
Pp. 55-68. Washington, D.C.
National Academy Press
John L. Ivy1
Since the early studies of Christensen and Hansen (1939a,b), the importance of dietary carbohydrates has been recognized with respect to endurance during sustained, prolonged exercise. Christensen and Hansen (1939a) demonstrated a high-carbohydrate diet would significantly enhance endurance during prolonged exercise. They also observed that time to exhaustion was accompanied by hypoglycemia and that ingestion of a carbohydrate supplement at the time of exhaustion rapidly returned the blood glucose concentration back to normal and allowed considerable additional exercise to be performed (Christensen and Hansen, 1939b). On the basis of these results, Christensen and Hansen (1939a,b) suggested that fatigue during prolonged aerobic exercise was the result of depletion of the body's carbohydrate stores. Since the time of their classic research, many studies have been conducted to examine the role of dietary carbohydrates and carbohydrate supplements on aerobic endurance. In general, these
John L. Ivy, Exercise and Physiology and Metabolism Laboratory, The University of Texas at Austin, Austin, TX 78712