Exercises, such as swimming and cycling, that allow muscles to work at a steady rate with a constant, adequate supply of oxygen-carrying blood, and that can therefore be sustained for long periods. Oxygen is used to release energy from the body’s stores. To fuel aerobic exercise, the muscles use fatty acid, burning it completely to produce energy, carbon dioxide, and water.
When performed regularly, aerobic exercises improve stamina and endurance. They encourage the growth of capillaries, improving blood supply to the cells. Aerobic exercises also improve body cells’ capacity to use oxygen and increase the amount of oxygen the body can use in a given time. The condition of the heart also improves. (See also exercise; fitness.)