How does exercise affect glucose levels?
Insulin is produced when the concentration of glucose (a simple form of sugar) in the body increases, such as after eating. Insulin stimulates muscle and fat cells to absorb the glucose they need as fuel for their activities. If you are fasting, your muscles burn fat for energy; after eating, your muscles burn glucose for energy. During exercise, excess glucose stored by the muscles in the form of a starch called glycogen is first used for energy. Your body burns glycogen for energy most often during short bursts of exercise, such as a quick sprint or a run to catch the bus. As the exercise continues, your muscles take up glucose at almost 20 times the normal rate. With prolonged exercise, free fatty acids become the major material for muscle energy production. Where do the fuels originate and what is the role of insulin? Glucose originates mainly from the liver, while free fatty acids originate from the breakdown of fats (triglycerides) in fatty tissue. Insulin levels are usually lowe
