A cardiac stress test is the recording of the heart's activity while you exercise. Your heart is monitored by using electrodes to record the electrical activity it makes. Your heart's activity will also be monitored by seeing how your blood pressure and pulse change over the course of the test.

Reasons for Test

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

  • To evaluate if complaints of chest pain are related to the heart
  • To determine if arteries to the heart have blockages or narrowing (coronary heart disease or CHD]]>)
  • To identify an irregular heart rhythm or passing out that occurs during or after exercise
  • To monitor the heart's response to treatment or procedures
  • To determine a safe level of participation before the start of an exercise regimen
  • To plan rehabilitation after a ]]>heart attack]]>

ECGs Revealing Cardiac Muscle Damage

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Possible Complications

A cardiac stress test presents minimal risk. Complications can include:

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

Technicians are alert for any signs of heart or lung problems. They are prepared to take immediate action if complications develop. A doctor (usually a cardiologist) will be readily available during the stress test as well.

What to Expect

Prior to Test

Your doctor may do the following:

  • Physical exam
  • Resting electrocardiogram (ECG, EKG)]]>—a test that records the heart's activity by measuring electrical currents through the heart muscle
  • ]]>Echocardiogram]]>—a test that uses sound waves (ultrasound) to examine the size, shape, and motion of the heart and the function of its valves
  • Review of your medicines. Some medicine should not be taken before testing.

In the time leading up to your procedure:

  • Do not eat or drink products with caffeine for 12-24 hours before testing.
  • Do not eat or drink anything except water for four hours before testing.
  • Do not smoke for several hours before testing.
  • 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 (most common) 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 have any symptoms that suggest heart problems. Significant changes in the ECG will also stop the test. After exercise is complete, your blood pressure, heart rate, and ECG will be monitored until levels return to normal.

A doctor may also order a blood-flow imaging exam, 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 to identify areas of the heart muscle that may not be receiving enough oxygen. A second set of images will be taken about an hour later, after you have rested.

A stress echocardiogram may also be done. This is an ultrasound to take pictures of the heart before and immediately 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 3-4 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 muscle
  • You develop chest pain or trouble breathing, especially if associated with ECG changes
  • Nuclear stress test results which show areas of your heart which are not receiving enough oxygen during exercise
  • Failure to adequately increase heart rate and/or blood pressure during exercise

A positive test may mean CHD, but not all patients who test positive have CHD. Based on the results of the test, your doctor will decide if further testing or treatment is needed.

Call Your Doctor

After the test, call your doctor if any of the following occurs:

  • Chest pain
  • Pounding in the chest
  • Dizziness or lightheadedness
  • Feeling extremely tired or having trouble breathing

In case of an emergency, call 911 immediately.