What is Aerobic Exercise?

Aerobic exercise is the type of moderate-intensity physical activity that you can sustain for more than just a few minutes with the objective of improving your cardiorespiratory fitness and your health. "Aerobic" means "in the presence of, or with, oxygen." You know you're doing aerobic exercise when your heart's thumping and you're breathing faster than you do at rest but you can sustain the activity for extended periods of time. I recommend the cue "warm and slightly out of breath" to determine if your activity level is aerobic. Walking, jogging, biking, dancing, and swimming are examples of activities that can be performed aerobically. Anaerobic, on the other hand, means "the absence of, or without, oxygen." Anaerobic exercise is performed at an intensity that causes you to get out of breath quickly and can be sustained for only a few moments. Weight lifting and sprinting are examples of anaerobic exercise.

Source: http://www.emedicinehealth.com