by EBSCO Medical Review Board
(Exercise Stress Test; Exercise Tolerance Test)


A cardiac stress test is a recording of the heart's activity during exercise. The heart is monitored using electrodes to record its electrical activity. Changes in blood pressure and pulse are measured during the test.

Reasons for Test

During physical activity, your body needs higher levels of oxygen. It gets oxygen from the blood. During exercise, the heart has to work harder to get blood to your organs. A cardiac stress test is used to see if your heart works well, even when it is working hard. The test is most often done to:

  • Evaluate whether complaints of chest pain are related to your heart
  • Determine if arteries to your heart have blockages or narrowing
  • Identify an irregular heart rhythm, or see if you pass out during or after exercise
  • Monitor your heart's response to treatment or procedures
  • Determine a safe level of activity before the start of an exercise plan
  • Plan rehabilitation after a heart attack
ECGs Revealing Cardiac Muscle Damage
Nucleus factsheet image
Copyright © Nucleus Medical Media, Inc.

Possible Complications

Problems from the procedure are rare, but all procedures have some risk. Your doctor will review potential problems, such as:

  • Developing chest pain
  • Developing an irregular heart rhythm
  • Having a heart attack (rare)

Technicians will be alert for any signs of heart or lung problems. Immediate action will be taken if complications happen. A doctor, most often a cardiologist, will be available during the stress test as well.

What to Expect

Prior to Test

Your doctor may review tests that were already done. Your medicine will be reviewed. Some medicine should not be taken before the test.

In the time leading up to your procedure:

  • Do not eat or drink products with caffeine for 12 to 24 hours before the test.
  • Do not eat or drink anything except water for 4 hours before the test.
  • Do not smoke for several hours before the test.
  • Wear comfortable clothing and walking shoes or exercise sneakers.
  • Bring a list of your current medicines to the test.
  • If you have diabetes, bring your glucose monitor to the test.

Description of Test

ECG electrodes will be attached to your chest. The electrodes are small, sticky patches with wires. Your resting blood pressure and ECG readings will be taken.

The cardiac stress test is done on a treadmill or a stationary bike. You will slowly start walking or riding. At regular intervals, the speed and elevation will be increased. Your ECG, blood pressure, heart rate, and symptoms will be closely monitored.

The test may be stopped early if you feel extremely tired, get chest pain, have trouble breathing, or if you have any symptoms that suggest heart problems. The test will also be stopped if there are significant changes in the ECG. After exercise is complete, your blood pressure, heart rate, and ECG will be monitored until levels return to normal.

A blood flow imaging exam may also be ordered. This is called a nuclear stress test. A small amount of radioactive chemical will be injected into a vein when you are exercising at your peak. Scans will be taken while you lie in different positions under a special camera. The images will help identify areas of the heart that may not be receiving enough oxygen. After you have rested for about an hour, a second set of images will be taken.

A stress echocardiogram may also be done. This is an ultrasound, which takes pictures of the heart before and right after exercise.

After Test

You may resume normal activities.

How Long Will It Take?

The exercise portion of the test generally takes less than 15 minutes. Your entire appointment will last about an hour. A nuclear stress test may take up to 3 to 4 hours.

Will It Hurt?

Exercise testing normally causes no pain.


A cardiologist will review the test results and send a report to your doctor. The report is often sent within 24 hours.

One or more of the following are considered a positive stress test:

  • ECG changes that show low oxygen supply to the heart
  • You develop chest pain or trouble breathing, especially if associated with ECG changes
  • Failure to properly increase heart rate and/or blood pressure during exercise
  • Nuclear stress test results that show areas of your heart that are not receiving enough oxygen during exercise

Your doctor may do more tests to confirm the diagnosis. Talk to your doctor about your results.

Call Your Doctor

Contact your doctor if you experience symptoms such as:

  • Chest pain
  • Lightheadedness
  • Feeling extremely tired or having trouble breathing

If you think you have an emergency, call for emergency medical services right away.


American Heart Association 

Heart Rhythm Society 


Canadian Cardiovascular Society 

Heart and Stroke Foundation of Canada 


Cardiac stress testing. EBSCO DynaMed website. Available at: Accessed March 5, 2021.

Darrow M. Ordering and understanding the exercise stress test. Am Fam Physician. 1999:59(2):401-410.

Exercise stress test. American Heart Association website. Available at: Accessed March 5, 2021.

What is cardiac stress testing? National Heart, Lung, and Blood Institute website. Available at: Accessed March 5, 2021.

Revision Information