Some heart problems, like blocked coronary arteries, are hard to detect because they don’t cause symptoms until your heart works very hard. A cardiac stress test is a standard test that checks how well your heart works during physical activity.
Keep reading to learn what happens during a stress test, what it can reveal, and signs you need a stress test.
What Is a Stress Test?
A stress test (also called an exercise stress test) is a very common, noninvasive test that examines your heart’s health. It helps your doctor identify problems with your heart’s muscles, valves, vessels, and electrical signals while you exercise.
The test checks:
- Blood flow through your heart.
- Blood pressure.
- Electrical signals that control your heartbeat.
- Heart rate and rhythm.
During an exercise stress test, you walk on a treadmill or ride a stationary bike while hooked up to an EKG (electrocardiogram) machine. If you cannot exercise, your health care provider can give you medication that makes your heart pump faster and harder.
When you exercise, healthy arteries dilate or widen to allow more blood and oxygen to flow to your heart. If you have blocked arteries, less blood can flow during exercise, appearing as abnormal readings on an EKG or blood pressure readings.
Other types of stress tests
The exercise stress test is the most common and basic type of cardiac stress test. However, in some cases, your doctor might recommend more advanced stress testing, such as:
- A stress echocardiogram. This test adds an echocardiogram (echo) before and immediately after you exercise on a treadmill or stationary bike. An echocardiogram uses an ultrasound wand to capture moving pictures of blood flow through your heart’s chambers and valves.
- A nuclear stress test (also called nuclear cardiac imaging). With this test, a medical professional injects a special tracer dye into a vein in your arm before your test. They will then scan your heart before and after exercise to see how much of the tracer is in your heart vessels. This tells your doctor if enough blood is flowing through your heart.
What Are Signs I Need a Stress Test?
Your doctor may order a cardiac stress test to evaluate these or other symptoms:
- Chest pain (angina), especially during physical activity.
- Exercise-induced irregular heartbeat (arrhythmia).
- Shortness of breath.
- Unexplained dizziness or lightheadedness.
Inadequate blood flow through your heart or heartbeat abnormalities might cause these symptoms. A stress test can give your doctor more information and tell them whether you need more advanced testing to diagnose heart problems.
You may also need a stress test if:
- You’re at a high risk of heart disease, and your doctor wants to catch any problems to prevent a heart attack.
- You have heart disease or heart failure, and your doctor wants to monitor your condition or treatment.
- You need surgery, and your health care team wants to ensure your heart is healthy enough.
- You want to start exercising after cardiac rehab, and your doctor wants to check your heart function during physical activity.
What Should I Expect During a Stress Test?
A basic exercise stress test is surprisingly fast and easy, but knowing what to expect is helpful.
Preparing for the test
Your health care provider may ask you to do a few things before your test, such as:
- Avoid coffee or other sources of caffeine or nicotine for up to 24 hours before the test.
- Avoid applying lotion or powder to your chest on the morning of the test.
- Avoid eating anything for several hours before the test.
- Stop taking certain medications the morning of the test.
- Wear comfortable clothes and walking shoes.
During the test
When it’s time for the test, a technician will apply electrodes (small, sticky sensors) to your chest. The electrodes will connect to an EKG machine, which measures your heart rate and rhythm during exercise. The tech will also place a blood pressure cuff on your arm to measure blood pressure during the test.
If you cannot exercise, a health care practitioner will also place an IV in your arm. They will give you medicine through the IV that makes your heart work harder. The medicine affects your heart like exercise and will wear off after about 20 minutes.
If you can exercise, you’ll walk on a treadmill or pedal a stationary bike. An exercise physiologist will ask you to start at an easy pace and gradually increase your intensity. They’ll monitor you the entire time, and you can stop if you experience chest pain, dizziness, or any problems.
The exercise test usually lasts about 15 minutes or until you reach your target heart rate, which varies depending on age. It ranges from 100 to 170 beats per minute at ages 20 to 75 to 128 beats per minute at age 70.
When the exercise physiologist gathers enough EKG information, you can stop exercising. They’ll continue to monitor your heart and blood pressure as you rest and your heart rate returns to normal. This usually takes another 15 minutes.
How Do I Understand My Stress Test Results?
A normal stress test result means your heart works as it should and you have healthy blood flow. Your doctor may tell you it’s safe to start an exercise program or have surgery if those were reasons for your stress test. If you take medication for heart disease, a normal stress test indicates it’s working well.
You can still benefit from a heart-healthy diet and lifestyle changes, if necessary, even with a routine stress test. These will help reduce your risk of heart problems as you age.
A typical stress test also suggests that heart problems are probably not the cause of symptoms like shortness of breath or chest pain. Your doctor may order other tests to determine what’s causing your symptoms.
An abnormal stress test result means blood flow through your heart isn’t optimal, perhaps because of a blockage or arrhythmia. If you had abnormal exercise stress test results, your doctor may recommend more advanced tests such as:
- An angiogram, which is a special x-ray test that takes pictures of your arteries.
- An exercise stress echocardiogram or nuclear stress test examines blood flow through your heart more closely during exercise.
Your heart must work well 24/7, whether at rest or working hard. A cardiac stress test is one way to ensure your heart is strong, healthy, and pumping as it should.
Editor's Note: This article was originally published on , and was last reviewed on .