A Guide to Stress Test Reason, Procedure, Risks and Results

Medically Reviewed By Uzochukwu Ibe, MD, MPH
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A stress test, also called a cardiac stress test, shows how exercise affects a person’s heart. For people who are unable to exercise, medication can make the heart work as it would during exercise. The test helps diagnose, monitor, or assess a person’s risk for heart disease. A stress test involves monitoring the heart’s electrical activity and other vital signs. It is performed while a person exercises at increasing levels of intensity, or after taking medication to mimic stress on the heart during exercise.

How your heart responds to the exercise stress can indicate possible cardiac problems. Doctors also use stress tests to monitor heart conditions and suggest an appropriate exercise program.

This article provides an overview of stress tests and what they can tell you about your heart.

What is a stress test?

Female running on treadmill during a stress test
simonkr/Getty Images

A stress test provides insight into how your heart responds to exercise. It determines how much exercise your heart can manage before experiencing a problem.

Doctors use stress tests to diagnose and monitor:

  • cardiac arrhythmias, or irregular heartbeats
  • coronary artery disease
  • cardiac ischemia, or not enough blood flow to the heart muscle
  • other types of heart disease

A stress test is a common diagnostic tool to monitor and diagnose heart conditions.

Types of stress tests

The types of stress tests include:

  • Standard or regular stress test: This is also called an exercise stress test. It involves walking on a treadmill or pedaling a stationary bicycle. If a medical condition prevents you from exercising, your doctor may suggest medication to mimic the stress on your heart during exercise. When medication is used, the test may be called a pharmacologic stress test.
  • Nuclear stress test: This test uses a radioactive dye given through an IV. It shows how well blood is flowing to the heart during exercise or medication. Nuclear stress tests include a thallium stress test, sestamibi (Cardiolite) stress test, and PET (positron emission tomography) stress test.
  • Stress echocardiogram: The stress echocardiogram uses sound waves to take moving pictures of your heart.

Why is a stress test performed?

Your doctor may recommend a stress test in order to see how well your heart handles work. It provides important information about your heart health in relation to your age, physical condition, and medical history.

A stress test is not a routine screening test. By itself, it cannot diagnose all types of heart conditions or predict future heart problems.

Doctors use stress tests to help diagnose or monitor the following conditions:

Your doctor may recommend a stress test if you are experiencing any of the following symptoms:

Your doctor may also perform a stress test to:

  • determine a safe and healthy exercise plan if you have heart disease or are at high risk of developing heart disease
  • further evaluate irregular heart test results such as changes on a standard ECG
  • monitor your heart condition after a heart attack, angioplasty, heart transplant, or heart bypass surgery

Who performs a stress test?

The following specialists can perform a stress test:

  • cardiologists
  • clinical cardiac electrophysiologists
  • interventional cardiologists
  • cardiac surgeons
  • advanced heart failure and transplant cardiologists

How is a stress test performed?

A stress test is designed to make your heart reach a target rate. Your doctor will determine your target heart rate based on your age, fitness level, heart health, and other factors.

A stress test can be performed in a doctor’s office or hospital setting. It takes about 30 minutes and generally includes these steps:

  1. You will wear loose comfortable clothing, or you may be offered a hospital gown. You will also wear a blood pressure cuff.
  2. A healthcare professional will attach electrodes to your chest, arms, and legs. These will be attached with wires to an ECG machine.
  3. You will begin the test by walking slowly on a treadmill or pedaling a stationary bike. The speed will gradually increase to raise the level of exercise intensity.
  4. Your healthcare professional may then have you breathe into a special tube to measure the amount of air you breathe out.
  5. When your heart reaches its target heart rate, you will slow down gradually.

For a nuclear stress test, your doctor will inject a safe radioactive dye into your body. Your healthcare team will then take pictures of your heart before and during exercise.

For a stress ECG, your doctor will take pictures of your heart using sound waves before and during exercise. They will watch your ECG and vital signs closely and stop the test if abnormalities occur.

After the test, you will rest until your heart rate returns to normal.

Your doctor can stop the test at any time if you do not feel well or experience symptoms such as:

  • chest pain
  • fatigue
  • dizziness
  • shortness of breath

After evaluating your test, your doctor will discuss the results with you during your visit or at a follow-up appointment.

Will I feel pain during a stress test?

A stress test should be painless. Tell your healthcare team immediately if you have chest pain or any other discomfort during or after your test.

What are the risks and potential complications of a stress test?

Stress tests are generally safe, but any medical procedure involves risks and potential complications.

A stress test carries a small risk of complications including:

Your healthcare team is trained and equipped to treat complications. They will monitor you closely during a stress test and stop if you experience any problems.

Reducing your risk of complications

You can reduce the risk of certain complications of a stress test by: 

  • notifying your healthcare team immediately of any concerns such as chest pain, palpitations, dizziness, or shortness of breath
  • telling your healthcare team about your medical history including any allergies or heart problems

How do I prepare for my stress test?

There are steps you can take before your stress test to help your healthcare team get the most accurate results. You can prepare for your stress test by:

  • answering all questions about your medical history and medications
  • not eating foods, drinking liquids, or consuming caffeine before your test, as directed by your doctor
  • stopping or taking your medications as directed by your doctor, and possibly stopping beta blockers

What can I expect after my stress test?

Stress tests do not usually require recovery time. However, if you are already in the hospital, you may remain there for further evaluation and treatment.

How will I feel after my stress test?

Most people return to normal activities after a stress test. You should not feel ill or have any symptoms after your test. Tell your doctor immediately if you experience symptoms such as dizziness, chest pain, or shortness of breath.

For a nuclear stress test, you will need to drink extra fluids to help flush the dye out of your body.

When can I go home?

Unless you are hospitalized, you will likely go home directly after the stress test. Patients sometimes stay to discuss the results with the doctor and get more tests.

When should I contact my doctor?

Contact your doctor if you have any concerns between appointments. Also alert them if you have any new symptoms or you are not responding to your medications. Seek emergency medical care if you have chest pain or shortness of breath.

Understanding the test results

Doctors organize stress test results into the following categories:

  • Positive or abnormal: The test detects signs that may indicate heart disease or other cardiac conditions.
  • Negative or normal: The test does not detect any heart abnormalities.
  • Equivocal: The test results are inconclusive.
  • Maximal or submaximal goal achieved: The individual was or was not able to reach the target heart rate during the test.

A stress test provides valuable information but is only one tool doctors use to diagnose possible heart conditions.

Frequently asked questions

Can a stress test show a blockage?

A stress test can identify symptoms of a blockage such as shortness of breath or difficulty completing the test. However, it does not identify blockages directly. A doctor can use nuclear imaging to see where any blockages might be located. This allows them to watch blood flow to the heart in real time.

How fast do you walk during a stress test?

The initial walking pace during a stress test is under 2 miles per hour. During the test, the speed and grade of elevation will increase about every 2 minutes. The goal is to increase the exercise intensity until you reach a target heart rate. The pace will vary from person to person depending on age, physical fitness, heart health, and other factors.

What does a positive stress test mean?

A positive stress test means your doctor observed symptoms that may indicate a heart problem, such as a blockage or coronary artery disease. If your results are positive, your doctor will talk to you about next steps. This includes refining the diagnosis and recommending appropriate treatment.

Summary

Stress tests are an important tool for diagnosing symptoms related to certain heart conditions. During an exercise stress test, you will walk on a treadmill or pedal a stationary bike until you reach your target heart rate. While exercising vigorously, your doctor can monitor your heart’s electrical activity, blood pressure changes, and symptoms like chest pain or dizziness.

If the stress test shows possible heart abnormalities, your doctor may recommend other tests or imaging scans. These will help them make a diagnosis and recommend treatment.

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Medical Reviewer: Uzochukwu Ibe, MD, MPH
Last Review Date: 2022 Jul 28
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