URL of this page: https://medlineplus.gov/lab-tests/stress-tests/

Stress Tests

What are stress tests?

Stress tests show how well your heart handles physical activity. Your heart pumps harder and faster when you exercise. Some heart disorders are easier to find when your heart is hard at work. During a stress test, your heart will be checked while you exercise on a treadmill or stationary bicycle. If you're not healthy enough to exercise, you'll be given a medicine that makes your heart beat faster and harder, as if you were actually exercising.

If you have trouble completing the stress test in a specified period of time, it may mean there is reduced blood flow to your heart. Reduced blood flow can be caused by several different heart conditions, some of which are very serious.

Other names: exercise stress test, treadmill test, stress EKG, stress ECG, nuclear stress test, stress echocardiogram

What are they used for?

Stress tests are most often used to:

  • Diagnose coronary artery disease, a condition that causes a waxy substance called plaque to build up in the arteries. It can cause dangerous blockages in blood flow to the heart.
  • Diagnose arrhythmia, a condition that causes an irregular heartbeat
  • Find out what level of exercise is safe for you
  • Find out how well your treatment is working if you've already been diagnosed with heart disease
  • Show if you are at risk for a heart attack or other serious heart condition

Why do I need a stress test?

You may need a stress test if you have symptoms of limited blood flow to your heart. These include:

  • Angina, a type of chest pain or discomfort caused by poor blood flow to the heart
  • Shortness of breath
  • Rapid heartbeat
  • Irregular heartbeat (arrhythmia). This may feel like a fluttering in your chest.

You may also need a stress test to check your heart health if you:

  • Are planning to start an exercise program
  • Have had recent heart surgery
  • Are being treated for heart disease. The test can show how well your treatment is working.
  • Have had a heart attack in the past
  • Are at a higher risk for heart disease due to health problems such as diabetes, family history of heart disease, and/or previous heart problems

What happens during a stress test?

There are three main types of stress tests: exercise stress tests, nuclear stress tests, and stress echocardiograms. All types of stress tests may be done in a health care provider's office, outpatient clinic, or hospital.

During an exercise stress test:

  • A health care provider will place several electrodes (small sensors that stick to the skin) on your arms, legs, and chest. The provider may need to shave excess hair before placing the electrodes.
  • The electrodes are attached by wires to an electrocardiogram (EKG) machine, which records your heart's electrical activity.
  • You will then walk on a treadmill or ride a stationary bicycle, starting slowly.
  • Then, you'll walk or pedal faster, with the incline and resistance increasing as you go.
  • You'll continue walking or riding until you reach a target heart rate set by your provider. You may need to stop sooner if you develop symptoms such as chest pain, shortness of breath, dizziness, or fatigue. The test may also be stopped if the EKG shows a problem with your heart.
  • After the test, you'll be monitored for 10–15 minutes or until your heart rate returns to normal.

Both nuclear stress tests and stress echocardiograms are imaging tests. That means that pictures will be taken of your heart during testing.

During a nuclear stress test:

  • You will lie down on an exam table.
  • A health care provider will insert an intravenous (IV) line into your arm. The IV contains a radioactive dye. The dye makes it possible for the health care provider to view images of your heart. It takes between 15–40 minutes for the heart to absorb the dye.
  • A special camera will scan your heart to create the images, which show your heart at rest.
  • The rest of the test is just like an exercise stress test. You'll be hooked up to an EKG machine, then walk on a treadmill or ride a stationary bicycle.
  • If you are not healthy enough to exercise, you'll get a medicine that makes your heart beat faster and harder.
  • When your heart is working at its hardest, you'll get another injection of the radioactive dye.
  • You'll wait for about 15-40 minutes for your heart to absorb the dye.
  • You'll resume exercising and the special camera will take more pictures of your heart.
  • Your provider will compare the two sets of images: one of your heart at rest; the other while hard at work.
  • After the test, you'll be monitored for 10-15 minutes or until your heart rate returns to normal.
  • The radioactive dye will naturally leave your body through your urine. Drinking lots of water will help remove it faster.

During a stress echocardiogram:

  • You will lie on an exam table.
  • The provider will rub a special gel on a wand-like device called a transducer. He or she will hold the transducer against your chest.
  • This device makes sound waves, which create moving pictures of your heart.
  • After these images are taken, you will exercise on treadmill or bicycle, as in the other types of stress tests.
  • If you are not healthy enough to exercise, you'll get a medicine that makes your heart beat faster and harder.
  • More images will be taken when your heart rate is increasing or when it's working at its hardest.
  • Your provider will compare the two sets of images; one of your heart at rest; the other while hard at work.
  • After the test, you'll be monitored for 10–15 minutes or until your heart rate returns to normal.

Will I need to do anything to prepare for the test?

You should wear comfortable shoes and loose clothing to make it easier to exercise. Your provider may ask you to not eat or drink for several hours before the test. If you have questions about how to prepare, talk to your health care provider.

Are there any risks to the test?

Stress tests are usually safe. Sometimes exercise or the medicine that increases your heart rate can cause symptoms such as chest pain, dizziness, or nausea. You will be monitored closely throughout the test to reduce your risk of complications or to quickly treat any health problems. The radioactive dye used in a nuclear stress test is safe for most people. In rare cases, it may cause an allergic reaction. Also, a nuclear stress test is not recommended for pregnant women, as the dye might be harmful to an unborn baby.

What do the results mean?

A normal test result means no blood flow problems were found. If your test result was not normal, it can mean there is reduced blood flow to your heart. Reasons for reduced blood flow include:

  • Coronary artery disease
  • Scarring from a previous heart attack
  • Your current heart treatment is not working well
  • Poor physical fitness

If your exercise stress test results were not normal, your health care provider may order a nuclear stress test or a stress echocardiogram. These tests are more accurate than exercise stress tests, but also more expensive. If these imaging tests show a problem with your heart, your provider may recommend more tests and/or treatment.

If you have questions about your results, talk to your health care provider.

References

  1. American Heart Association [Internet]. Dallas (TX): American Heart Association Inc.; c2018. Exercise Stress Test [cited 2018 Nov 9]; [about 4 screens]. Available from: https://www.heart.org/en/health-topics/heart-attack/diagnosing-a-heart-attack/exercise-stress-test
  2. American Heart Association [Internet]. Dallas (TX): American Heart Association Inc.; c2018. Non-Invasive Tests and Procedures [cited 2018 Nov 9]; [about 4 screens]. Available from: https://www.heart.org/en/health-topics/heart-attack/diagnosing-a-heart-attack/noninvasive-tests-and-procedures
  3. American Heart Association [Internet]. Dallas (TX): American Heart Association Inc.; c2018. What Is a Stress Test? [cited 2018 Nov 9]; [about 5 screens]. Available from: https://www.heart.org/-/media/data-import/downloadables/pe-abh-what-is-a-stress-test-ucm_300453.pdf
  4. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2018. Echocardiogram: Overview; 2018 Oct 4 [cited 2018 Nov 9]; [about 3 screens]. Available from: https://www.mayoclinic.org/tests-procedures/echocardiogram/about/pac-20393856
  5. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2018. Electrocardiogram (ECG or EKG): Overview; 2018 May 19 [cited 2018 Nov 9]; [about 3 screens]. Available from: https://www.mayoclinic.org/tests-procedures/ekg/about/pac-20384983
  6. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2018. Stress test: Overview; 2018 Mar 29 [cited 2018 Nov 9]; [about 3 screens]. Available from: https://www.mayoclinic.org/tests-procedures/stress-test/about/pac-20385234
  7. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2018. Nuclear stress test: Overview; 2017 Dec 28 [cited 2018 Nov 9]; [about 3 screens]. Available from: https://www.mayoclinic.org/tests-procedures/nuclear-stress-test/about/pac-20385231
  8. Merck Manual Consumer Version [Internet]. Kenilworth (NJ): Merck & Co., Inc.; c2018. Stress Testing [cited 2018 Nov 9]; [about 2 screens]. Available from: https://www.merckmanuals.com/home/heart-and-blood-vessel-disorders/diagnosis-of-heart-and-blood-vessel-disorders/stress-testing
  9. National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Coronary Heart Disease [cited 2018 Nov 9]; [about 2 screens]. Available from: https://www.nhlbi.nih.gov/health-topics/coronary-heart-disease
  10. National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Echocardiography [cited 2018 Nov 9]; [about 2 screens]. Available from: https://www.nhlbi.nih.gov/health-topics/echocardiography
  11. National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Stress Testing [cited 2018 Nov 9]; [about 2 screens]. Available from: https://www.nhlbi.nih.gov/health-topics/stress-testing
  12. UF Health: University of Florida Health [Internet]. Gainesville (FL): University of Florida Health; c2018. Exercise stress test: Overview [updated 2018 Nov 8; cited 2018 Nov 9]; [about 2 screens]. Available from: https://ufhealth.org/exercise-stress-test
  13. UF Health: University of Florida Health [Internet]. Gainesville (FL): University of Florida Health; c2018. Nuclear stress test: Overview [updated 2018 Nov 8; cited 2018 Nov 9]; [about 2 screens]. Available from: https://ufhealth.org/nuclear-stress-test
  14. UF Health: University of Florida Health [Internet]. Gainesville (FL): University of Florida Health; c2018. Stress echocardiography: Overview [updated 2018 Nov 8; cited 2018 Nov 9]; [about 2 screens]. Available from: https://ufhealth.org/stress-echocardiography
  15. University of Rochester Medical Center [Internet]. Rochester (NY): University of Rochester Medical Center; c2018. URMC Cardiology: Exercise Stress Tests [cited 2018 Nov 9]; [about 4 screens]. Available from: https://www.urmc.rochester.edu/cardiology/patient-care/diagnostic-tests/exercise-stress-tests.aspx
  16. University of Rochester Medical Center [Internet]. Rochester (NY): University of Rochester Medical Center; c2018. Health Encyclopedia: Dobutamine Stress Echocardiogram [cited 2018 Nov 9]; [about 2 screens]. Available from: https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=92&contentid=p07968
  17. UR Medicine: Highland Hospital [Internet]. Rochester (NY): University of Rochester Medical Center; c2018. Cardiology: Cardiac Stress Tests [cited 2018 Nov 9]; [about 4 screens]. Available from: https://www.urmc.rochester.edu/highland/departments-centers/cardiology/tests-procedures/stress-tests.aspx
  18. UR Medicine: Highland Hospital [Internet]. Rochester (NY): University of Rochester Medical Center; c2018. Cardiology: Nuclear Stress Tests [cited 2018 Nov 9]; [about 4 screens]. Available from: https://www.urmc.rochester.edu/highland/departments-centers/cardiology/tests-procedures/stress-tests/nuclear-stress-test.aspx

The medical information provided is for informational purposes only, and is not to be used as a substitute for professional medical advice, diagnosis or treatment. Please contact your health care provider with questions you may have regarding medical conditions or the interpretation of test results.

In the event of a medical emergency, call 911 immediately.