The body can use glycogen as an energy source when aerobic exercise lasts
http://www.livestrong.com/article/487122-the-body-can-use-glycogen-as-an-energy-source-when-aerobic-exercise-lasts-how-long/
The body can use glycogen as an energy source when aerobic exercise lasts for an extended period of time. Glycogen is a form of glucose (sugar) that is stored in the liver and muscles and serves as a readily available source of energy.
During aerobic exercise, the body primarily relies on a mix of carbohydrates and fats for fuel. Initially, the body uses the easily accessible glucose from the bloodstream for energy. However, as the duration of exercise increases and the body's glucose stores in the bloodstream become depleted, it starts to break down glycogen to release glucose.
To get the answer to your question, you need to understand how the body utilizes different energy sources during aerobic exercise and how exercise duration affects glycogen utilization. This knowledge can be obtained through studying concepts related to human physiology, metabolism, and exercise science, which are often covered in courses such as biology, exercise physiology, or sports science. Additionally, scientific research articles or textbooks in these fields can provide more detailed information on the topic.