DescriptionAn in-depth report on the benefits and types of exercise.
Exercise's Effects on the Heart
Inactivity is one of the four major risk factors for coronary artery disease, on par with smoking, unhealthy cholesterol, and high blood pressure. However, exercise helps improve heart health in people with many forms of heart disease and can even reverse some risk factors, such as some of the effects of smoking.
Like all muscles, the heart becomes stronger and larger as a result of exercise so it can pump more blood through the body with every beat and sustain its maximum level with less strain. The resting heart rate of those who exercise is also slower because less effort is needed to pump blood.
People who exercise the most often and vigorously have the lowest risk for heart disease, but any exercise is beneficial. Studies consistently find that light to moderate exercise is even beneficial in people with existing heart disease. However, anyone with coronary artery disease should seek medical advice before beginning a workout program.
Heart- and Stroke-Protective Benefits of Exercise on the Heart and Blood
Exercise has a number of effects that benefit the heart and circulation, including improving cholesterol and lipid levels, reducing inflammation in the arteries, assisting weight loss programs, and helping to keep blood vessels flexible and open. Studies continue to show that physical activity and avoiding high-fat foods are the two most successful means of reaching and maintaining heart healthy levels of fitness and weight.
In their 2003 guideline on exercise for the prevention of cardiovascular disease, the American Heart Association recommended that individuals perform moderate-intense exercise for 30 minutes on most days of the week. This recommendation supports similar exercise guidelines issued by the Centers for Disease Control and Prevention and the American College of Sports Medicine.
Coronary Artery Disease. People who maintain an active lifestyle have a 45% lower risk of developing heart disease than do sedentary people. Experts have been attempting to define how much exercises is needed to produce heart benefits. In 2002, a well-conducted study on overweight adults confirmed previous research that reported beneficial changes in cholesterol and lipid levels, including lower LDL levels (the so-called bad cholesterol), even when people performed low amounts of moderate or high intensity exercise (e.g., walking or jogging 12 miles a week). However, more intense exercise is required to significantly change cholesterol levels, notably increasing HDL (the so-called good cholesterol). An example of such a program would be jogging about 20 miles a week. Such benefits in the study occurred even with very modest weight loss, suggesting that overweight people who have trouble losing pounds can still achieve considerable heart benefits by exercising.
Some studies suggest that for the greatest heart protection, it is not the duration of a single exercise session that counts but the total daily amount of energy expended. Therefore, the best way to exercise may be in multiple short bouts of intense exercise, which can be particularly helpful for older people.
Resistance (weight) training has also been associated with heart protection. It may offer a complementary benefit to aerobics by reducing LDL levels. Exercises that train and strengthen the chest muscles may prove to be very important for patients with angina.
Effects of Exercise on Blood Pressure. Regular exercise helps keep arteries elastic, even in older people, which in turn ensures blood flow and normal blood pressure. Sedentary people have a 35% greater risk of developing hypertension than athletes do.
It should be noted that high-intensity exercise may not lower blood pressure as effectively as moderate-intensity exercise. In one study, moderate exercise (jogging two miles a day) controlled hypertension so well that more than half the patients who had been taking drugs for high blood pressure were able to discontinue their medication. Experts recommend at least 30 minutes of exercise on most -- if not all days. Studies have indicated that yoga and tai chi, an ancient Chinese exercise involving slow, relaxing movements, may lower blood pressure almost as well as moderate-intensity aerobic exercises.
Anyone with existing hypertension should discuss an exercise program with their physician. Before starting to exercise, people with moderate to severe hypertension should lower their pressure and be able to control it with medications. They should avoid caffeinated beverages, which increase heart rate, the workload of the heart, and blood pressure during physical activity. Everyone, and especially people with high blood pressure, should breath as normally as possible through each exercise. Holding the breath increases blood pressure.
Effects of Exercise on Heart Failure. Traditionally, heart failure patients have been discouraged from exercising. Now, exercise performed under medical supervision is proving to be helpful for select patients with stable heart failure.
Experts warn, however, that exercise is not appropriate for all heart failure patients.
Effects of Exercise on Stroke. The effects of exercise on stroke are less established than on heart disease, but most studies are positive on its benefits. The following are some examples:
Starting an Exercise Program for High-Risk Individuals
Anyone with heart disease or risk factors for developing heart disease or stroke should seek medical advice before beginning a workout program. Patients with heart disease can nearly always exercise safely as long as they work out under medical supervision. Still, it is often difficult for a physician to predict health problems that might arise as the result of an exercise program. At-risk individuals should be very aware of any symptoms warning of harmful complications while they exercise.
Some experts believe that anyone over 40 years old, whether or not they are at risk for heart disease, should have a complete physical examination before starting or intensifying an exercise program. Some physicians use a questionnaire for people over 40 to help determine whether they require such an examination:
Those who answer yes to any of the following questions should have a complete medical examination before developing an exercise program.
Stress Test. A stress test helps determine the risk for a heart event from exercise. Anyone with a heart problem or history of heart disease should have a stress test before embarking on an exercise program. Experts currently also recommend this test before a vigorous exercise program for older persons who are sedentary, even in the absence of known or suspected cardiovascular disease. It is expensive, however, and some experts believe that it may not be necessary for many older people with no evident health problems or risk factors. They recommend instead a carefully monitored program, starting out with low-intensity exercises and gradually building up.