Why is exercise or physical activity important?

Regular aerobic physical activity increases your fitness level and capacity for exercise. It also plays a role in both primary and secondary prevention of cardiovascular disease. Physical inactivity is a major risk factor for heart disease and stroke and is linked to cardiovascular mortality.

Regular physical activity can help control blood lipid abnormalities, diabetes and obesity. Aerobic physical activity can also help reduce blood pressure.

The results of pooled studies show that people who modify their behavior and start regular physical activity after heart attack have better rates of survival and better quality of life. Healthy people — as well as many patients with cardiovascular disease — can improve their fitness and exercise performance with training.

How can physical activity help condition my body?

• Some activities improve flexibility, some build muscular strength and some increase endurance.
• Some forms of continuous activities involve using the large muscles in your arms or legs. These are called endurance or aerobic exercises. They help the heart by making it work more efficiently during exercise and at rest.
• Brisk walking, jumping rope, jogging, bicycling, cross-country skiing and dancing are examples of aerobic activities that increase endurance.

How can I improve my physical fitness?

Programs designed to improve physical fitness take into account frequency (how often), intensity (how hard), and time (how long). They provide the best conditioning.

AHA Recommendation

For most healthy people:

For health benefits to the heart, lungs and circulation, perform any moderate-to-vigorous-intensity aerobic activity for at least 30 minutes on most days of the week at 50–85 percent of your maximum heart rate. You can accumulate 30 minutes in 10 or 15 minute sessions. What's important is to include physical activity as part of a regular routine.

These activities are especially beneficial when done regularly:

• brisk walking, hiking, stair-climbing, aerobic exercise
• jogging, running, bicycling, rowing and swimming
• activities such as soccer and basketball that include continuous running

The training effects of such activities are most apparent at exercise intensities that exceed 50 percent of a person's exercise capacity (maximum heart rate). If you're physically active regularly for longer periods or at greater intensity, you're likely to benefit more. But don't overdo it. Too much exercise can give you sore muscles and increase the risk of injury.

What about moderate-intensity activities?

Even moderate-intensity activities, when performed daily, can have some long-term health benefits. They help lower the risk of cardiovascular diseases. Here are some examples:

• walking for pleasure, gardening and yard work
• housework, dancing and prescribed home exercise
• recreational activities such as tennis, racquetball, soccer, basketball and touch football

What risk factors are reduced?

Regular physical activity can also help reduce or eliminate some of these risk factors:

• High blood pressure — Regular aerobic activities can lower blood pressure.
• Cigarette smoking — Smokers who become physically active are more likely to cut down or stop smoking.
• Diabetes — People at their ideal weight are less likely to develop diabetes. Physical activity may also decrease insulin requirements for people with diabetes.
• Obesity and overweight — Regular physical activity can help people lose excess fat or stay at a reasonable weight.
• High levels of triglycerides — Physical activity helps reduce triglyceride levels. High triglycerides are linked to developing coronary artery disease in some people.
• Low levels of HDL — Low levels of HDL ("good") cholesterol (less than 40 mg/dL for men/less than 50 mg/dL for women) have been linked to a higher risk of coronary artery disease. Recent studies show that regular physical activity can significantly increase HDL cholesterol levels and thus reduce your risk.

What are other benefits of physical activity?

• Physical activity builds healthy bones, muscles and joints, and reduces the risk of colon cancer. Millions of Americans suffer from illnesses that can be prevented or improved through regular physical activity.
• Physical activity also helps psychologically. It reduces feelings of depression and anxiety, improves mood and promotes a sense of well-being.
• The 1996 Surgeon General's Report on Physical Activity also suggests that active people have a lower risk for stroke.

When should I consult my doctor?

Some people should consult their doctor before they start a vigorous exercise program. See your doctor or other healthcare provider if any of these apply to you:

• You have a heart condition or you've had a stroke, and your doctor recommended only medically supervised physical activity.
• During or right after you exercise, you often have pains or pressure in the left or mid-chest area, left neck, shoulder or arm.
• You've developed chest pain or discomfort within the last month.
• You tend to lose consciousness or fall due to dizziness.
• You feel extremely breathless after mild exertion.
• Your doctor recommended you take medicine for your blood pressure, a heart condition or a stroke.
• Your doctor said you have bone, joint or muscle problems that could be made worse by the proposed physical activity.
• You have a medical condition or other physical reason not mentioned here that might need special attention in an exercise program (for example, insulin-dependent diabetes).
• You're middle-aged or older, haven't been physically active, and plan a relatively vigorous exercise program.

If none of these is true for you, you can start on a gradual, sensible program of increased activity tailored to your needs. If you feel any of the physical symptoms listed above when you start your exercise program, contact your doctor right away. If one or more of the above is true for you, an exercise-stress test may be used to help plan an exercise program.

Excerpt from the American Heart Association

(This list was developed from several sources, particularly the Physical Activity Readiness Questionnaire, British Columbia Ministry of Health, Department of National Health and Welfare, Canada, revised 1992.)