Aerobic Fitness Author:John Mason Improve your aerobic fitness levels and your overall health. Learn about the body, its functions and how to assist others in obtaining their aerobic fitness goals. Aerobic activity is anything that makes the heart beast faster than its normal level. For aerobic exercise to be useful the heart rate must be sustained for a least 20 minutes. This b... more »ook shows how to plan an effective aerobic workout, through exercise or work. The illustrations demonstrate simple exercises.« less