Prolonged exercise, such as endurance, can result in depletion of muscle and liver glycogen. When muscle glycogen is depleted the horse can continue to exercise on fat, but at a slower speed. When liver glycogen is depleted blood glucose cannot be maintained. Energex increases plasma glucose with only a small increase in insulin making the increased glucose available to the muscles and brain both during exercise to aid glycogen sparing, and after exercise for optimal glycogen replenishment and recovery.