Stress test

Overview

A stress test shows how the heart works during physical activity. It also may be called an exercise stress test. Exercise makes the heart pump harder and faster. A stress test can show changes with blood flow within the heart.

A stress test usually involves walking on a treadmill or riding a stationary bike. A healthcare professional watches your heartbeat, blood pressure and breathing during the test. People who can't exercise may be given a medicine that affects the heart like exercise does.

Your healthcare professional may recommend a stress test if you have symptoms of coronary artery disease or an irregular heartbeat, called an arrhythmia.

A stress test can help:

• Decide what treatment is needed.
• Show how well heart treatment is working.
• Show how serious a heart condition is.

Why it's done

A stress test may be done to:

• Diagnose coronary artery disease. The coronary arteries are the major blood vessels that bring blood and oxygen to the heart. Coronary artery disease happens when these arteries get damaged or diseased. Cholesterol deposits in the heart arteries and inflammation usually cause coronary artery disease.
• Diagnose irregular heartbeats, also called arrhythmias. An arrhythmia can cause the heart to beat too fast or too slowly.
• Learn if heart treatment is working, or decide on a treatment. If you've already been diagnosed with a heart condition, an exercise stress test can help your healthcare team know if your treatment is working. The test results also help your healthcare professional decide on the best treatment for you.
• Check the heart before surgery. A stress test can help your healthcare professionals determine if surgery, such as a valve replacement or a heart transplant, might be a safe treatment for you.

If an exercise stress test doesn't show the cause of symptoms, your healthcare professional may recommend a stress test with imaging. Such tests include a nuclear stress test or stress test with an echocardiogram.

Risks

An exercise stress test is generally safe. Complications are rare. Possible complications of an exercise stress test are:

• Low blood pressure. Blood pressure may drop during or right after exercise. The drop might cause dizziness or fainting. The problem will likely go away after the exercise stops.
• Irregular heart rhythms, called arrhythmias. Arrhythmias that occur during an exercise stress test usually go away soon after the exercise stops.
• Heart attack, also called myocardial infarction. Although very rare, it's possible that an exercise stress test could cause a heart attack.

How you prepare

Your healthcare professional can tell you how to prepare for your exercise stress test.

Food and medicine

You may be told not to eat, drink or smoke for a time before a stress test. You may need to stay away from caffeine the day before and the day of the test.

Some medicines might have an effect on stress tests. Ask your healthcare professional if you can take your medicines before the test.

If you use an inhaler for asthma or other breathing, bring it to the test. Tell your healthcare team that you use an inhaler.

Clothing and personal items

Wear or bring comfortable clothes and walking shoes.

What you can expect

An exercise stress test usually takes about an hour, including the preparation time and the time it takes to do the actual test. The exercise part takes only around 15 minutes. It usually involves walking on a treadmill or pedaling a stationary bicycle. If you can't exercise, you may get medicine that affects the heart like exercise does.

Before a stress test

Your healthcare professional usually asks questions about your medical history and how often and how hard you exercise. This helps your healthcare team decide how much you can exercise during the test. Your healthcare professional usually listens to your heart and lungs to check for anything that might affect your test results.

During a stress test

A healthcare professional places sticky patches called electrodes on your chest and sometimes your arms and legs. Body hair may be shaved to help the patches stick. The patches record the heartbeat. Wires connect the patches to a computer, which shows or prints the test results. This part of a test is called an electrocardiogram, commonly called an ECG.

A cuff on your arm checks your blood pressure during the test. You may be asked to breathe into a tube during the test to show how well you're able to breathe during exercise.

Exercise may be on a treadmill or stationary bike. The pace is easy at first. As the test continues, the exercise gets harder. You can use the railing on the treadmill for balance. Don't hang on tightly, as this may affect the results.

Exercise continues until your heart rate reaches a target level. You might need to stop sooner if you get symptoms such as:

• Moderate to severe chest pain.
• Severe shortness of breath.
• Unusually high or low blood pressure.
• An irregular heartbeat.
• Dizziness.
• Fatigue.

If you can't exercise during the stress test, a healthcare professional gives you medicine through a needle in your vein, called an IV. The medicine increases blood flow to the heart, similar to exercise.

You can stop the test anytime you're too uncomfortable. Your healthcare professional might stop the test if there are concerns about the way your heart is acting during the test.

After a stress test

After exercising, you may be asked to stand still for several seconds and then lie down for a while. Your healthcare professional watches for changes in your heart rate and breathing as you recover from the exercise.

When the test is done, you may return to your usual activities unless your healthcare team tells you otherwise.

Results

Stress test results help your healthcare professional plan or change your treatment. If the test shows that your heart is working well, you may not need more tests.

If the test suggests that you might have coronary artery disease, you may need a test called a coronary angiogram. This test can show blockages in the heart arteries.

If the test results are OK but your symptoms get worse, your healthcare professional might recommend more testing. Tests may include a nuclear stress test or a stress test that includes an echocardiogram. These tests give more details about how the heart works.