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Heart health: What is a stress test?

This test can help show how well the heart is working. It may be used to diagnose a variety of heart problems or to help determine what sort of activity level is safe after a heart attack or heart surgery.

How well does your heart stand up to hard work and exercise? A stress test can provide the answer.

These tests, usually done on a treadmill or exercise bike, help show if your heart is pumping well and getting enough oxygen, according to the American Heart Association.

Why might I need a stress test?

Your doctor may order a stress test if there's reason to suspect you're at risk for coronary heart disease (CHD).

In CHD, fatty deposits in the arteries interfere with blood flow to the heart, preventing it from getting enough blood and oxygen. This can put you at risk for a heart attack.

A stress test also can help detect abnormal heart rhythms and problems with blood pressure, according to the National Heart, Lung, and Blood Institute (NHLBI).

Symptoms that may lead a doctor to order a stress test include shortness of breath, chest pain, rapid heartbeat or a fluttering feeling in your chest.

A doctor also may order a stress test after a person has had a heart attack or heart surgery in order to determine what sort of exercise and activity levels are safe for that person, notes the NHLBI.

What happens during the test?

During the stress test:

  • You'll wear monitors to measure your heart rate, blood pressure and breathing, and your heart's electrical activity (this is an electrocardiogram, or EKG).
  • You'll walk on the treadmill or ride the exercise bike for about 15 minutes—or until you reach a target heart rate established by your doctor.
  • Gradually, the pace will quicken and walking or pedaling will become more difficult, as if you're going uphill.
  • You'll stop walking or pedaling, and a medical professional will check your heart or blood pressure while you rest.
  • You may be asked to breathe into a tube during the test so your doctor can see how well you're breathing and can measure the gases you exhale.

Stress tests are very safe, but a medical professional will be present to help if you have any problems. You can stop the test at any time if you feel uncomfortable. Be sure to mention if you feel dizzy or have chest pain.

If you're not able to use the treadmill or bike because of a disability, a physician can do a stress test using medicine that temporarily makes your heart work harder.

Preparing for the test

The test may be done in a doctor's office or at the hospital. You'll want to wear comfortable shoes and clothing and may be told to avoid caffeine for a day before the test. If you use an inhaler for asthma or another breathing problem, be sure to bring it along.

Imaging tests

In some cases, a doctor may want to perform imaging tests such as an echocardiogram or PET scan as part of a stress test. These tests show how well blood flows inside the heart and can help the doctor diagnose CHD.

After the test

Following the stress test, you can return to normal activities. If results are normal, no further testing or treatment may be necessary. If results are abnormal, your doctor may recommend other tests to help diagnose the problem.

Talk to your doctor if you have any questions or concerns about the health of your heart.

Reviewed 2/6/2023

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