We all know, or think we know, the benefits of aerobic exercise. They include an improvement in cardiovascular fitness and in muscular strength and endurance; a reduction in LDL cholesterol (the “bad cholesterol”) and an increase in HDL (the “good cholesterol”); a decrease in blood pressure; a loss of body fat and better weight control; better control of blood sugar in diabetics and decreased shortness of breath, especially if you have lung problems.

There is also a great psychological benefit to aerobic exercise: reduced stress, decreased fatigue, increased self-esteem, and a general sense of well-being. The benefits of aerobic exercise can be obtained at any age and become more important as we age. It has been said that for every mile you walk, you extend your life by one full minute.

However, more than 60% of American adults do not get the minimum recommended amount of physical activity and more than 25% of adults are sedentary. Why?

Common reasons given for not exercising include: I don’t have time … I’m too tired … I don’t know what type of exercise to do … I have a medical condition (usually a “bad heart,” backache, or knee pain) … I’m too heavy … I’m short of breath … I can’t afford the gym … It’s boring … I’m too old.

And there are more innovative excuses: my uncle lived to be 106 and never exercised (we should all be blessed with such good genes) … It’s too cold outside in winter … I’m always outside … enough in the job …

You get the idea.

Almost any form of physical activity is helpful, but a good exercise program should include at least 30 minutes of moderate aerobic exercise on most days of the week. Examples of aerobic exercise are brisk walking, jogging, biking, swimming, and aerobic dancing. An effective exercise program should include:

• Warm-up, 3 to 5 minutes. A warm-up gradually increases your heart rate and blood flow to your heart and muscles, preparing them for exercise. To warm up, do the activity you have chosen to do (for example, walking or cycling), but at a slower pace during the warm-up period.
• Aerobic activity, at least 30 minutes (gradually increase from 15 minutes over several weeks). With aerobic exercise, you use more oxygen to burn calories and get the extra energy you expend. Exercise within your target heart rate zone (target charts are available at gyms, on the web, and at your doctor’s office).
• Chill for 3 to 5 minutes. Cooling down allows your heart rate, breathing, and blood pressure to return to normal and allows you to stretch better.
• Stretching, 5 to 10 minutes. Stretching will improve your flexibility, decrease muscle pain, and help you relax. It is important to stretch the muscles that you used during exercise. Hold each stretch for 15-20 seconds, but don’t stretch to the point of pain.
• Strength training, which is a very important component of a good exercise program.

Before starting an exercise programCheck with your doctor if you are over 40 or have a history of medical problems. If you really have special needs, a reasonable exercise program can usually be designed for you.

And those excuses? Forget them and let’s get started!