Some of the best forms of aerobic activity are the traditional sports. If you get together and play basketball twice a week with friends, this alone might be enough to keep you fit and healthy. Some people should consult their doctor before they start a vigorous aerobic activity program.
Regular aerobic activity improves your fitness as your heart becomes stronger and begins to work better. The result is that the heart can pump more blood (thus increasing oxygen delivery to the tissues) with each heartbeat. As your aerobic fitness increases, you can work out longer with greater intensity and recover quicker at the end of the session.
Aerobic activity is often coined either High Impact or Low Impact. High-impact aerobic activity includes actions that take both feet off the floor, thus causing more jarring of the joints when the body weight hits the floor again. An example of Low Impact is walking while High Impact is jogging or jumping up and down.
Aerobic activities use the arm and leg muscles and give the heart (and lungs) a continuous workout. Anaerobic activities build and tone muscles but are not as beneficial to the heart and lungs as aerobic activities.
Lasty, The important thing is to get some kind of aerobic activity, and to make it something that you enjoy enough to keep with it.