This study determined if recreational type of endurance exercise is limited by a short-term fast, such as an overnight fast or benefited by a carbohydrate supplement prior to and during endurance exercise.
Six individuals ran at 70% VO2max for 90 min under three dietary conditions (fed, fasted for 16 to 18 h, fasted plus CHO).
RPE, RER, BG (blood glucose), and La (lactate) were similar between conditions throughout 90 min of exercise. FFA was higher (P ≤ 0.05) only in the fed and fasted groups after exercise.
The psychosomatic sensation, physiologic, and metabolic data all indicated that endurance exercise for up to 90 min for fit individuals is not limited by a short-term fast or enhanced by carbohydrate supplementation. These findings are of interest to persons who exercise to maintain and enhance health and are not concerned with elite performance.
The authors are with the Dept of Applied Health Science, Wheaton College, Wheaton, IL 60187.