A cardiopulmonary stress test (CPX test) is a special treadmill test. This test takes an ECG and measures how your lungs work while you exercise. Your doctor may ask you to take a CPX test to see if you have any cardiac or respiratory problems during exercise and to determine how well the heart pumps blood to the muscles. This information is needed to determine the best exercise plan for you.

For the test, ECG wires will be attached to your chest for an electrocardiogram of your heart. You will breathe into a breath analyzer that measures the gas exchange in your lungs. An oximeter will be placed on your finger to determine how much oxygen is in your blood while you exercise. Your blood pressure and pulse will be taken during the test.

You will start out by walking slowly on the treadmill. You will be asked to gradually increase your speed and incline. You can stop the test at any time. If at any point during the test you feel as if you have had enough, give the “thumbs down” signal to the exercise physiologist and doctor. They will slow down the treadmill and stop the test.

The results of the test will help your doctor choose a target heart rate for you to reach when you exercise and decide the best exercise for you.

Dyspnea on exertion and exercise intolerance are common problems in many conditions and diseases. Cardiopulmonary exercise testing makes possible to assess the exercise response in patients with abnormalities which are either underestimated or not detectable at rest. The method permits simultaneous assessment of circulatory and ventilatory reserves and can determine aerobic capacity, anaerobic threshold, the ventilatory response and the appearance of hypoxemia. Peak exercise oxygen uptake is the variable most often used, because of its physiological and prognostic value. One can use this information to evaluate the nature and severity of disease, its progression over time and its response to therapy.

How do I prepare for a cardiopulmonary stress test?

Wear loose comfortable clothing and walking shoes the day of the test. Eat a light meal and take your medicines just as you normally would. An exercise physiologist, a doctor and a nurse will be present during your test.

How is this test different than a standard treadmill stress test?

Cardiopulmonary Metabolic Exercise Stress Testing (CMET) is a noninvasive measurement of cardiac, respiratory and functional capacities that replaces the traditional model of treadmill stress testing. It is a sensitive diagnostic tool that provides extensive data on each of these areas for the physician.

With prevalence adjusted risk stratification, CMET provides the best Sensitivity and Specificity of all noninvasive tests-thus a higher predictive value.

What are some common problems with traditional stress testing?

1. Low Sensitivity and Specificity
2. Higher incidence of false positives
3. Poor Estimate of O2 Consumption
4. Limited estimate of functional capacity & METS
5. Often inappropriate protocols & poor patient tolerability
6. High rate of indeterminate & inconsistent results and poor reproducibility

What is most unique about this test?

Although most complete physical examinations include a check of the heart at rest with an electrocardiogram (ECG or EKG), the results are limited to what is seen at the time of the examination and are limited in their ability to detect disease or dysfunction. The CMET challenges the cardiopulmonary (heart and lungs) system and the entire physical body to determine the capacity of each system. This type of test provide tremendous amount of information that relates not only present health but for future health outcomes such as your risk for cardiovascular or pulmonary disease and your capacity to do any type of physical activity.

The advantage of this type of test can be illustrated by the analogy of a mechanic taking an automobile for a test drive, as opposed to trying to evaluate the vehicle while idling or even turned off! So, a progressively challenging exercise test provides a more sensitive evaluation.