Let’s discuss the ins and outs of an aerobic exercise program. If you haven’t already, first look over the exercise overview.

Aerobic exercise is doing something moderately strenuous for a period of time, sufficient to raise your heart rate and improve cardiovascular fitness. Common activities include walking, jogging, bicycling (outdoors or on a stationary bike), swimming, “water walking” (in the shallow end of a pool), and using exercise machines like the treadmill, stair-stepper, or elliptical exerciser. Vigorous sports like tennis, basketball, or racquetball certainly count. Science clearly shows that people who engage in moderate activity (e.g., walking at a medium pace for half an hour four times a week) are much healthier and more functional than those who are sedentary or just do activities about the house.

Aerobics are the first place to start if you are recovering from an injury or have a painful medical condition like arthritis or myofascial pain. People with diabetes and heart and lung disease almost always benefit from regular aerobics, although they should have medical guidance on how intensely to exercise. Cardiac and pulmonary rehabilitation programs are medically supervised aerobic exercise classes for people with illness affecting heart or lungs (e.g., angina or emphysema). Formal rehabilitation has been shown to dramatically improve function, lessen symptoms, and reduce the risk of further illness.

See your doctor before starting an exercise program if you’ve had a serious illness or face significant limitations in your ability to function.

Aerobic exercise is the easiest kind to do. Figure out what you like to do that makes you pant and sweat. Decide on a convenient place and time. Do what you enjoy! Try it out, a little bit at first if you’re not fit, and see what happens. Modify your program as needed. If you run into problems, see your doctor. If problems with knees or hips interfere with walking, often a good place to start is walking in the shallow end of a swimming pool.

With aerobics, it’s important to work hard enough but not overdo it. Once you’ve build up fitness, your routine should leave you feeling pleasantly tired. While exercising you should be too short of breath to sing but not too short of breath to talk. When you stop, it should take time to cool off. Many people benefit from mixing up different kinds of aerobics exercises during the week: walking, bicycling, elliptical machine, etc.

Some people make a point of closely monitoring their heart rate, aiming for a target pulse of 60-70% of their maximal rate. I don’t specialize in exercise or physical training, but I don’t see the point of this — unless your cardiologist gives you a heart rate limit, or you’re training for competition. My perspective is a lot more informal: exercise to the point you feel you’re working and feel good.

Half an hour of moderate exercise four times a week provides proven health benefits. Increasing this to six hours a week is even better. You can substitute interval training 3-4 days a week and get a terrific workout in much less time.