If you have chest pain or shortness of breath, your doctor may recommend a cardiac stress test. Though the name may make you nervous, there’s no reason to stress about a stress test.
“Stress, in the case of a stress test, really means exercise,” says Seth Uretsky, MD, a board-certified cardiologist with Atlantic Health System, who adds that these diagnostic tests are quick and non-invasive. The most basic stress tests take less than an hour to complete.
What is a stress test?
A stress test is a tool heart doctors (cardiologists) use to check how well your heart works during exercise.
An abnormal stress test can be a sign of a heart condition like coronary artery disease (CAD) — a blockage in one or more of the heart’s arteries. Suspected CAD is one of the most common reasons cardiologists order stress tests.
Cardiologists also use stress tests to look for signs of an irregular heartbeat (arrhythmia), check the effectiveness of certain heart treatments and evaluate the heart before certain surgeries.
Types of stress tests
There are several types of stress tests, but each has the same goal: to put stress on the heart to see how it functions under a heavier workload.
During a stress test, doctors use exercise or medication to “stress” your heart.
- Exercise stress test: During an exercise stress test, a technician places stickers, called electrodes, on your chest. These electrodes are attached to wires (leads) that send information about your heart’s electrical activity to an electrocardiogram (EKG) machine. With electrodes and wires in place, you will walk on a treadmill or pedal a stationary bike to increase your heart rate and force it to work harder.
- Pharmacological stress test: A pharmacological stress test is similar to an exercise stress test but without physical exercise. During a pharmacological stress test, doctors give you a medication designed to mimic the conditions of exercise.
“Exercise or medicine is how we stress the heart,” Dr. Uretsky says. “But we also have to decide if we need to take images of the heart, too.”
During a stress test with imaging, a health care provider will take pictures of your heart before and at peak exercise or pharmacological stress. They may do this using a type of ultrasound called an echocardiogram (echo), a nuclear stress test or using a magnetic resonance imaging (MRI) machine.
Your doctor may order a nuclear stress test for a more detailed look at your heart. During this test, health care providers inject a small amount of radioactive dye into your vein. Then, they use imaging tools to watch the dye — also called a tracer — as it moves through your heart during exercise.
Imaging tools, like positron emission tomography (PET) and MRI give doctors even more advanced pictures of your heart. If your doctor recommends a heart PET scan or heart MRI with your stress test, they will use medication, not exercise, to stress your heart.
How do doctors decide which stress test to use?
The stress test you need depends on your symptoms, your risk for heart disease and your ability to exercise. Your doctor will also evaluate your ability to have radiation before recommending a nuclear stress test.
An exercise stress test is often the first choice for people who can walk but don’t need advanced imaging.
If you cannot exercise, a pharmacological stress test may be your best option. You may also need a pharmacological stress test if your doctor wants to use an MRI or PET scan to make pictures of your heart.
Preparing for a cardiac stress test
Regardless of which test your doctor orders, it’s important to avoid applying lotions or oils to your skin before a stress test. These products can interfere with the electrodes that supply information to the EKG.
Your doctor may also caution you to avoid caffeine before a stress test — especially a nuclear stress test — as this can interfere with the test results.
Wear comfortable clothing and sneakers if you are having an exercise stress test.
“For an exercise stress test, it’s important that you go in with the mentality that you want to exercise as much as you can,” Dr. Uretsky says. “That will give your doctor much more information about your heart’s function.”
The bottom line with stress tests
Cardiac stress tests can detect severe coronary artery blockages. But these tests are just one tool doctors use to evaluate your heart.
A “normal” test isn’t always a sign that you’re in the clear.
“If you have a normal test, that doesn’t necessarily mean you don’t have heart disease,” Dr. Uretsky says. “It just means you may not have a significant blockage. Your doctor may order additional tests, like a coronary CT scan, or they may even recommend medication to prevent problems down the road.”