What is a stress test?

During a stress test, you will usually exercise by walking or running on a treadmill, or by peddling a stationary bicycle. While your heart is working hard, one of several types of stress tests will be used to evaluate how much blood flow is getting to the heart and how effectively the heart is pumping. Occasionally, your doctor may use a stress test that only measures the electrical activity in your heart while you exercise. In other instances, your doctor may couple your stress test with an echocardiogram, which uses ultrasound waves to evaluate your heart's shape and movement while beating. A third type of stress test is a nuclear test. In this case, you will receive an injection of a special radioactive tracer, and a nuclear camera will be used to take color-coded pictures of the heart that measure blood flow before, during and after exercise.

If you are not strong enough to exercise, your doctor may choose to give you a special medication to make the heart beat quickly and forcefully. In essence, the medication makes your heart "exercise" when you cannot. This type of stress test is called a pharmacologic stress test, because medicine is used in place of exercise to make the heart beat fast. During a pharmacologic stress test, the test of electrical activity, ultrasound imaging or nuclear imaging can be coupled with the artificial exercise to evaluate the heart, just as with real exercise.

Dr. Steven C. Port, MD
Cardiologist (Heart Specialist)

Stress testing is performed for a variety of reasons, but the most common is to evaluate symptoms that could indicate a partial blockage of one or more of the coronary arteries, which bring nutrition and oxygen to the heart muscle.

The majority of stress tests involve exercise, either on a treadmill or bicycle, while an electrocardiogram, which detects low-voltage electrical activity of the heart through electrodes on the chest, is recorded. Symptoms, changes in the electrocardiogram and, occasionally, changes in blood pressure may indicate the presence of a coronary artery blockage.

For a significant number of individuals, an exercise test is not possible. For those people, the heart may be stressed by a drug.

For many people, stress testing with an electrocardiogram alone is inadequate to make a diagnosis and imaging devices are coupled with the stress test for more accuracy.

An exercise stress test, also known as ETT or a treadmill test, helps physicians determine the presence and/or extent of heart disease. When a person exercises, the heart must work harder to provide oxygen-rich blood to the working muscles. If a person has some form of heart disease, such as coronary artery disease, heart rhythm disorders (arrhythmias) or abnormalities within the heart muscle, the heart may not be able to pump blood efficiently. When this happens, a person may feel chest discomfort, palpitations, shortness or breath, lightheadedness or dizziness. Some patients, such as diabetics, may not feel anything at all.

Why is a stress test ordered?

  • to help diagnose coronary artery disease
  • to evaluate possible heart-related symptoms such as chest pain, palpitations, shortness of breath or lightheadedness
  • to determine an appropriate and safe exercise level
  • to check the effectiveness of heart-related procedures such as cardiac catheterization with stenting, angioplasty or coronary artery bypass grafting
  • to check the effectiveness of certain heart-related medications such as beta-blockers or anti-arrhythmics
  • to predict the risk of heart attack

A stress test is a technique that involves stressing the heart and monitoring the heart's reaction. A stress test helps to assess the heart's capacity for work. The test can use exercise, medication, or both to induce stress and can use electrocardiography, echocardiography and nuclear imaging to monitor and assess the heart.

A stress test puts the heart under a small degree of stress, so doctors can determine whether or not blood is flowing to the heart properly.

There are different types of “stress tests” that can be used to evaluate the heart. The simplest is an exercise test, which is performed on a treadmill or stationary bicycle for people with suspected or known heart disease. The test records heart rate and blood pressure. Sticky electrodes are attached to the chest, shoulder and hip and are connected to a machine that records heart rate and blood pressure while exercising. An echocardiogram may also be performed during and immediately after exercising (stress echocardiogram). Some problems with the heart are not seen when the heart is at a calm, resting state. Exercise testing allows doctors to “work” the heart and evaluate it during times of activity and stress. This is a non-invasive test, meaning nothing is put into the body during the test. Since the purpose of the test is to exercise, it is important to dress appropriately, including comfortable clothes and shoes meant for activity.

Other types of “stress testing” include giving medications by vein while performing an echocardiogram or cardiac MRI to make the heart work harder. Sometimes abnormalities may be more easily identified if the heart is made to intentionally work harder.

A stress test is a diagnostic test for heart failure. The test examines how the blood vessels and heart respond to physical exertion. A stress test consists of walking or running on a treadmill or pedaling a bicycle to determine how the heart and blood vessels function when working hard. For people who cannot perform tests on a treadmill or bicycle, a drug is administered intravenously that simulates conditions of physical exertion. This test is often conducted in conjunction with an echocardiogram or a nuclear heart scan.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.