Anaerobic means without oxygen. This form of metabolism uses carbohydrates in the form of glucose and glycogen, for immediate energy production. Anaerobic metabolism fuels short bursts of activity when your body requires energy faster than the cardiovascular system can provide it. Our bodies draw energy from the food we eat. Carbohydrates are stored in the bloodstream and muscles as glucose or glycogen.
Excess food is stored in the body as fat.
Short, intense activities such as weightlifting or sprinting are fueled by anaerobic metabolism. For steady, continuous activity, your body switches to aerobic metabolism for energy. Once your body switches from anaerobic to aerobic metabolism, moderate levels of activity can be sustained by aerobic metabolism alone. Unfortunately, one of the by-products of anaerobic metabolism is lactic acid, a harmful waste product that causes muscle pain and fatigue. Improving Endurance Muscular endurance relies on the body's stores of glucose and glycogen for energy.