Exercise (Physical Activity)

AHA Scientific Position

Physical inactivity has been established as a major risk factor for the development of coronary artery disease. It also contributes to other risk factors including obesity, high blood pressure and a low level of HDL cholesterol. Even moderate intensity physical activity such as brisk walking is beneficial when done regularly for a total of 30 minutes or longer on most days.

Why is exercise or physical activity important?

Regular aerobic physical activity increases a person's capacity for exercise. It also plays a role in both primary and secondary prevention of cardiovascular disease. There is a relationship between physical inactivity and cardiovascular mortality.

Exercise can help control blood lipid abnormalities, diabetes and obesity. Aerobic exercise also has an independent, modest blood-pressure-lowering effect for certain groups of people with high blood pressure.

The results of pooled studies show that persons who modify their behavior after heart attack to include regular exercise have better rates of survival. Healthy persons - as well as many patients with cardiovascular disease - can improve their exercise performance with training.

How can physical activity or exercise help condition my body?

• Some activities improve flexibility, build muscular strength and/or increase endurance.
• Some forms of continuous activities involve using the large muscles in your arms or legs, called aerobic exercises. They specifically benefit the heart because they make the heart work more efficiently during exercise and at rest.
• Brisk walking, jumping rope, jogging, bicycling, cross-country skiing and dancing are examples of aerobic exercises that increase one's endurance capacity.

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), and provide the best conditioning. The FIT Formula:

F = frequency (days per week)

I = intensity (how hard, e.g., easy, moderate, vigorous) or percent of heart rate

T = time (amount for each session or day)

AHA Recommendation

For most healthy people:
For health benefits to the heart, lungs and circulation, perform any vigorous activity for at least 30 minutes, 3-4 days each week at 50-75 percent of maximum heart rate. Moderate intensity physical activities for 30 minutes on most days provide some benefits. Physical activity need not be strenuous to bring health benefits. What is important is to include activity as part of the regular routine.

Activities that are especially beneficial when performed regularly include

• 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). Adults who maintain a regular routine of physical activity of longer duration or greater intensity are likely to have greater benefits. However, physical activity should not be overdone, since too much exercise can result in injury.

What about lower-intensity activities?

For people who are not able to exercise vigorously or who are sedentary: Scientific evidence also supports the notion that even moderate-intensity activities, when performed daily, can have some long-term health benefits. They help lower the risk of cardiovascular diseases. Such activities include:

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

What risk factors are reduced?

Exercise can also help reduce or eliminate some of these risk factors:

• High blood pressure - Regular exercise is associated with lower blood pressure.
• Cigarette smoking - Smokers who exercise vigorously and regularly are more likely to cut down or stop cigarette smoking.
• Diabetes - People at their ideal weight are much less likely to develop diabetes. Exercise may also decrease a diabetic's insulin requirements.
• Obesity and overweight - Exercise can help people lose excess fat or stay at a reasonable weight.
• Low levels of HDL - Low levels of HDL (one of the cholesterol-carrying proteins in the blood) have been linked to an increased risk of coronary artery disease. Recent studies have shown that regular physical

When should I consult my doctor?

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

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

(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.)

©2000, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited.

The information in the American Heart Association (AHA) Web site is not a substitute for medical advice or treatment, and the AHA recommends consultation with your doctor or healthcare professional.