An Exercise stress test is a common test that doctors use to diagnose coronary artery disease. The test helps doctors see how the heart performs during exercise. You may also hear exercise stress tests called exercise tolerance tests, stress tests, exercise EKGs, or treadmill tests.

An exercise stress test may also use echocardiography (called a stress echocardiogram) or radioisotope dyes that are injected into the bloodstream (called nuclear stress tests). When these tests are done, doctors can tell more about the structure and blood flow of the heart.

How it works?
During a stress test, you will wear small metal disks called electrodes. The electrodes are connected to wires called leads, which are connected to a machine with a television monitor that records the electrical activity of your heart (EKG). This screen can also show pictures from a stress echocardiogram and nuclear stress test. By watching this screen, doctors can record your heartbeat while you are exercising.

Sometimes, a patient is too sick to exercise. In these cases, patients are given a drug that has the same effect on the body as if they had been exercising.

What to expect?
Do not eat or drink for 4 hours before the test, especially items that contain caffeine, which is found in coffee, tea, sodas, chocolate, and some over–the–counter pain relievers. Also, be sure to ask your doctor about any medicines you are taking, and whether you should stop taking them before the test.

A technician will use an alcohol swab to clean the areas of your skin where the electrodes will be placed. The alcohol may feel cold. Then, electrodes will be placed on your chest and back. The electrodes are attached to an electrocardiograph machine, which records your heart’s electrical activity. A healthy person’s electrocardiogram has a certain pattern, and changes in that pattern can tell doctors if there is a problem with your heart.

You will also wear a blood pressure cuff around your arm, which will be used to watch your blood pressure during the test. Before the test, doctors will record your blood pressure and pulse. They will also record your heart’s electrical activity before you start exercising (called a resting EKG). You will also wear the electrodes during exercise and for about 10 minutes more after exercise.

During the test, you will be asked to walk on a treadmill. Every 2 or 3 minutes, your doctor or the technician will increase the speed and slope of the treadmill, which will make you feel like you are walking uphill. Your doctor or a technician will look for changes in the electrocardiogram patterns and blood pressure levels, which may tell doctors that your heart is not getting enough oxygen. Other signs of coronary artery disease include chest pain or unusual shortness of breath while you are exercising.

At the end of the test, your doctor will give you a cool–down phase where you may be asked to lie down or sit quietly.