Glucose is an elementary sugar and primary source of energy for the muscles and brain. During exercise, it travels through the blood and is utilized by the active muscles to provide rapid energy.
Endurance athletes rely on glucose to maintain intense efforts and fuel aerobic energy expenditure. They stabilize blood glucose through consumption of substances such as gels, sport beverages, or normal foods and through the breakdown of stored glycogen in the liver. Quick-release glucose sources are able to rapidly enhance performance but consuming excessive quantities without meeting energy demands can cause digestive upset. Regulation of glucose is extremely critical to slowing fatigue and enhancing endurance performance.