Final answer:
Consumption of 75 grams of glucose before exercise increases plasma glucose and insulin levels, facilitating glucose absorption and reducing the rate of muscle glycogen utilization.
Step-by-step explanation:
Research studies reveal that the consumption of 75 grams of glucose 30 minutes before exercise results in both increased plasma glucose levels and increased plasma insulin levels. After consuming glucose, the bloodstream experiences a rise in glucose concentration.
This stimulates the pancreatic beta cells to release insulin into the blood. Insulin is crucial for the absorption of glucose by liver hepatocytes, and by adipose and muscle cells. Within these cells, glucose can be converted to glucose-6-phosphate and stored as glycogen, which is later used as an energy source. Furthermore, insulin is involved in promoting the synthesis of protein in muscle tissues.
During exercise, muscle glycogen utilization typically increases to meet the higher energy demands. However, due to the presence of elevated insulin levels, there could be a subsequent decrease in the rate of muscle glycogen utilization as glucose available in the blood is used preferentially.