September 7, 2012
Dear Mayo Clinic:
I just read that the treadmill stress test is no longer recommended. What's the reasoning behind this? I've had the test before, and it seems like a good way to find heart problems.
A treadmill stress test can be helpful if a doctor suspects someone has heart problems or if a person is at high risk for heart disease. However, this test is no longer recommended for people at low risk for heart disease who do not have symptoms. For that group, the test is not needed because assessing risk factors such as age, smoking, cholesterol, blood pressure, diabetes and family history has been shown to be nearly as effective in identifying an individual's potential for heart disease.
A treadmill stress test gathers information about how well your heart works as you exercise. Because exercise makes your heart pump harder and faster than it does during most daily activities, the test may be able to reveal problems within your heart that might not be noticeable otherwise.
During the stress test, you walk on a treadmill while an electrocardiogram, or ECG, records the electrical signals that trigger your heartbeats. Before you start, sticky patches — called electrodes — are placed on your chest, legs and arms. They are connected by wires to the ECG machine. A blood pressure cuff is placed on your arm to check your blood pressure during the test.
You start slowly. As the test progresses, the speed and incline of the treadmill increases. The goal is to have your heart work hard for about eight to 12 minutes to thoroughly monitor its function. You continue exercising until you develop symptoms that do not allow you to continue. Occasionally your doctor may stop the test sooner for other reasons.
A common reason doctors use an exercise stress test is to look for coronary artery disease. In this condition, the arteries that deliver blood to the heart muscle are narrowed or completely blocked. Coronary artery disease is the most common cause of death in the United States. Many patients with coronary artery disease have symptoms, such as shortness of breath or chest discomfort during physical activity. But a large number of people who have this disease do not have any symptoms, and their first sign of a problem is a heart attack.
Because of this, it has been a common practice in the U.S. to screen patients for coronary artery disease during routine physical exams by doing a treadmill stress test. The U.S. Preventive Services Task Force, a group of medical experts from around the country, looked at the evidence of following this practice. They found that for people who are at low risk for coronary artery disease and do not have any symptoms, there is little evidence that a treadmill stress test can accurately predict who will suffer a heart attack.
When used as a screening test in low risk people, the results of the treadmill test are occasionally misleading and can suggest that a problem is present when in fact none exists. Clarifying this issue may require performing more invasive and expensive testing, such as a coronary angiogram — a procedure used to closely examine the heart's arteries.
Instead of a treadmill stress test, talk to your doctor about your risk for coronary artery disease. If your age, family history, cholesterol levels, smoking, blood pressure or other medical conditions point to the possibility that you could develop the disease, you and your doctor can decide on the best way to watch for heart problems over time. In some cases, that could mean eventually doing a treadmill stress test.
For most people at low risk, the best approach is to see your doctor for regularly scheduled checkups, and follow a lifestyle that makes it less likely you will develop heart disease. You should stay active, eat a low-fat diet, control your cholesterol and blood pressure, not smoke, and maintain a healthy weight.
— Todd Miller, M.D., Cardiovascular Diseases, Mayo Clinic, Rochester, Minn.