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Photo of exercise equipment, including a bicycle, treadmill and computer.
Exercise (stress testing) equipment including bicycle, treadmill, and computer.

Photo of a patient with pulmonary equipment on her nose and mouth and a technician assisting her.
A technician and patient preparing for cardiopulmonary exercise testing.

A patient performing an exercise test using a treadmill.
A patient performing an exercise test using a treadmill.

Photo of a physician sitting at a computer and interpreting a patient's exercise test.
A physician interpreting a patient's cardiopulmonary exercise test.

Cardiopulmonary Exercise Test (CPET) at the Clinical Center

Patient Information

The researchers and staff of the National Heart, Lung, and Blood Institute and the Clinical Center welcome you.

Preparing for your Cardiopulmonary Exercise Test (CPET)

This information will help you understand and actively take part in your Cardiopulmonary Exercise Test (CPET). With your cooperation, these important tests will provide helpful information for your doctors to use during your stay at the Clinical Center.

What are Cardiopulmonary Exercise Tests (CPET)?

This test allows your doctor to learn how your lungs, heart and muscles react to exercise. Cardiopulmonary exercise tests may be performed on a stationary bike or a treadmill. As you ride a bike or walk on the treadmill, we measure how much air you breathe, how much oxygen you require and how fast and efficiently your heart beats. To measure the amount of air that you breathe you may either have to wear a face mask or a mouth piece, similar to that used for pulmonary function tests (PFT). In this case your nose will be pinched closed by a soft nose clip. An EKG (electrocardiogram) will check your heart’s electrical activity.

Why are CPETs done?

You may have CPETs for many reasons, for example, as a precaution before surgery, to check the status of your lung or heart disease or as part of your role in research. CPETs also help your doctor know whether you need to use oxygen during exercise and determine which types of activities you can perform without oxygen.


There is no preparation for CPETs, but it is best that you be relaxed. Wear comfortable, loose-fitting clothing and avoid belts or girdles that may make it harder for you to breathe. Women should wear bras. Wear comfortable, flat shoes that will not slip off while you are biking or walking. You may take breathing medications before exercising. If you smoke, avoid smoking for at least 8 hours before testing. Do not eat for two hours before the test, and do not drink liquids one hour before the test. Ask your doctor for other instructions, especially if you have heart disease, experience chest pain, or take medications that control your heart rate. Inform the doctor or nurse about any temporary or permanent condition that could affect your ability to move, walk, bear weight, or keep your balance. If possible, discuss this when you are first scheduled for the test. It is also important that the doctor and cardiopulmonary technologist conducting the test have this information. Try to be as well rested as possible. You may need to reschedule the test if you feel unwell (for example, if you have a cold). If you do not feel you can give your maximum exercise effort, contact your nurse or doctor before the test.

Test explanation and consent

Your CPET will be done in one of the pulmonary function laboratories of the Pulmonary-Critical Care Medicine Branch.

Before the test begins, the cardiopulmonary technologist or supervising physician will explain it to you. Feel free to ask questions and voice concerns at this time. When you understand what will happen, you will be asked to sign an informed consent document for the test to be performed. To monitor your heart during exercise, adhesive patches, called electrodes, will be put on your chest. Your chest will be cleansed with alcohol and shaved in some areas (if necessary) before these electrodes are placed. You will be asked about symptoms you have had with exercise in the past. Describe, as completely as you can, any chest discomfort, breathing problems, lightheadedness or dizziness, fluttering in the chest, weakness, fatigue, or anything else you think may be relevant. Also, mention anything you feel while you are being prepared for the test.

Overview of CPET

A doctor will be with you throughout the test. Your heart rate and rhythm, your blood pressure, breathing rate, oxygen consumption, and oxygen saturation (finger or forehead probe) will be checked during the test.
  • After a warm-up period lasting three minutes during which you will walk the treadmill or ride the bike slowly, the treadmill’s pace and incline or bike work load (resistance) will increase progressively (every 1-3 minutes).
  • It is important that you describe anything you feel as you exercise.
  • If you become short of breath, the cardiopulmonary technologist or supervising physician may ask you to rate it as, mild, moderate, or severe. If you have chest discomfort, you will be asked to describe it as best you can and rate it on a scale of 1 to 10 (1 is very mild; 10 is very severe). This helps the doctor know how you are doing and gives us a better way to compare how you feel before and after the test.
  • Keep riding the bike or walking the treadmill until you are told to stop or until you are too short of breath to continue or are physically exhausted. The cardiopulmonary technologist or physician may stop the test if your oxygen saturation drops to low levels or the EKG shows signs of heart injury.
  • During the recovery stage, keep walking or biking as the treadmill slows down or the load is taken off the bike. Do not jump off the treadmill. While you rest, your breathing, heart rate and oxygen level will continue to be monitored.

After the Procedure

  • You can eat and drink as usual.
  • Depending on how you feel, you may go about your normal routine or take it easy if you feel tired.
  • Do not take a hot shower for at least an hour after the test. Your blood vessels expand with exercise and need time to return to normal. A hot shower may expand them more, causing low blood pressure and dizziness.
  • Please remember, our staff is here to help you. If you have any questions about the tests, please feel free to ask. Your technologists, doctors, and nurses are here to help you at all times.


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