The word aerobic means with oxygen. When you exercise, your body needs
an extra supply of oxygen, which your lungs take in from the air. Without that supply of oxygen
your body would break down preventing you from continuing exercising.
Aerobic exercise is any repetitive activity that you do long enough and hard
enough to challenge your heart and lungs. In order to work your heart and lungs hard enough,
you must get your largest muscle groups involved. They include your legs, glutes, back and chest.
A few aerobic exercise examples would be running, cycling, and walking.