The type of carbohydrate eaten after exercise can affect the rate of glycogen synthesis as well. The Role of Insulin Enhancers Insulin is a hormone released by the pancreas in response to carbohydrate consumption. One of insulin's main functions is helping transport glucose into liver and muscle tissues, where it is stored as glycogen. Insulin also stimulates release of the enzyme glycogen synthase, which helps convert glucose to glycogen. Timing is key when it comes to muscle glycogen replenishment.
Muscle cells are most sensitive to insulin two hours after exercise.
Assuming enough carbohydrates are available, elevated blood-insulin levels after exercise expedite the transport of glucose into muscle cells, where it is converted to glycogen. After two hours, muscle cells become more resistant to insulin and remain so for several hours. Because insulin plays such a vital role in replenishing glycogen stores after exercise, researchers have focused on enhancing insulin release during recovery. Studies show that protein, when combined with carbohydrates, almost doubles the insulin response. So it seems logical to include protein in a recovery sports drink.