What Is a Treadmill Exercise Stress Test?

Treadmill Heart Health Test

A treadmill stress test.
A treadmill stress test.. Fuse/Getty Images

What is an Exercise Stress Test?

You may be used to hitting the treadmill at the gym and but now your doctor wants to put you on a treadmill in the lab. What is she looking for? An exercise stress test is a tool your physician may use to assess your heart health. It is also called a treadmill test or an exercise test.

The stress test can reveal if there is reduced blood flow in the arteries that supply the heart, often a sign of blockage.

During exercise, healthy coronary arteries dilate more than those with blockage. Narrowed arteries provide less blood (and less oxygen) to certain areas of the heart. The lack of oxygen can cause symptoms such as chest pain or inappropriate shortness of breath. An EKG done during the stress test may show abnormalities that help the physician determine where the blocked arteries are.

Who Might Have a Stress Test

Having symptoms of coronary artery disease or having significant risk factors for CAD are the main reasons your doctor may recommend a stress test. It is considered the appropriate first step for screening for these diseases. It may also be given if you complain of unusual fatigue, shortness of breath or irregular heartbeat during exercise. It is also often done if you are about to start a cardiac rehabilitation program or starting an exercise program.

Preparing for the Treadmill Stress Test

Be sure to tell your doctor beforehand all medications, herbs, vitamins, and supplements you have been taking.

You may be instructed to fast or refrain from smoking for four hours before the test. Dress for walking on a treadmill with athletic shoes and loose-fitting clothing you'll be able to walk or jog in.

What to Expect During the Test

Typically, your resting heart rate and blood pressure are recorded, and adhesive electrodes are attached to your torso.

You will also have a blood pressure cuff on your arm. You start walking on the treadmill at a very slow speed. Over minutes, the speed and elevation are increased. The test is generally stopped when you reach your target heart rate, but this is up to your physician. You may be asked to breathe into a tube for a couple of minutes.

During the test they measure your heart rate, blood pressure, breathing rate, electrocardiogram and how tired you feel.

Is There Any Risk in This Test?

You should only have the same small risk that you would have from doing a fast walk or a jog. But it is done surrounded by medical professionals and equipment, so it will be a safer environment in case you have a heart problem during the test. Discuss any fears you have about it with your doctor ahead of time.

What Do the Results Tell You?

A stress test can generally diagnose disease in approximately two-thirds of those with coronary artery disease. The accuracy is lower (about 50%) when patients have narrowing in a single coronary artery or higher (greater than 80%) when all three major arteries are involved.

Approximately 10% of patients may have a "false-positive" test (when the result is falsely abnormal in a patient without coronary artery disease). You should receive initial results at the end of your test. However, the official result may take a few days to complete.

The results of the test may help confirm or rule out a diagnosis of heart disease. If you have a history of coronary artery disease, the study will help confirm that you are stable or that a new blockage is developing. The results may cause your doctor to modify your treatment or have additional testing performed (cardiac catheterization, Echo Stress test, or a nuclear stress test).

Sources:

Fihn SD, et.al. "2014 ACC/AHA/AATS/PCNA/SCAI/STS focused update of the guideline for the diagnosis and management of patients with stable ischemic heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines, and the American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons." J Am Coll Cardiol. 2014 Nov 4;64(18):1929-49. doi: 10.1016/j.jacc.2014.07.017. Epub 2014 Jul 28.

Michael A. Chen, MD, PhD. "Exercise Stress Test." MedLine Plus, 4/20/2015. U.S. National Library of Medicine, NIH.

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