Glycogen metabolism refers to the processes of glycogen synthesis and breakdown in the body. Glycogen, a stored form of glucose, is primarily found in the liver and muscles. When energy is needed, glycogen is broken down into glucose through a process called glycogenolysis, which is regulated by hormones like glucagon and epinephrine. Conversely, when there is an excess of glucose, the body converts it into glycogen through glycogenesis. This process is stimulated by the hormone insulin. Glycogen serves as a crucial energy reserve, allowing the body to maintain blood sugar levels and provide energy during physical activity.