Your Doctor and Machines Track Your Responses to Exercise
The American Heart Association states that during a cardiac stress test, you walk on a treadmill while connected to devices. Your doctor will use a blood pressure machine to monitor how your blood pressure and heart rate respond to the exercise. Electrocardiogram pads will be placed on various areas of your body to monitor your heart's rhythm. You may need to breathe into a mask so your rate of oxygen consumption can be measured. In some cases you will have an IV inserted so your doctor can inject thallium to monitor your circulatory system. In addition, your doctor will ask you questions about how tired you are, how hard you feel that you are working or if you experience chest pain, dizziness, shortness of breath or other symptoms suggestive of heart disease.
Your Heart is Forced to Work Harder
As you begin to walk and your doctor slowly increases the speed and incline of the treadmill, your heart must pump harder to deliver the additional blood and oxygen needed by the body to sustain the activity. You will be pushed to a level that feels difficult, but your doctor can stop the test at any time if you become too fatigued. The goal is to bring you all the way up to your target heart rate and then slowly cool you down to see how your heart performs under exertion and how it recovers from the exercise.
Your Blood Pressure and Heart Rate Changes Indicate Disease
Your heart rate should rise in an appropriate proportion to the level of exertion. In addition, it should return to a resting rate when you stop the test. Your systolic blood pressure should also go up with exertion and your diastolic pressure should only go up slightly. Like your heart rate, your blood pressure should return to normal after the test has stopped. If your heart rate and/or blood pressure do not rise, go up too fast or too much or take a long time to return to normal, it may signify that your heart is not functioning properly.
Electrocardiograms or Echocardiograms Monitor the Heart's Activity and Structure
According to the NYU Langone Medical Center, electrogardiogram tests monitor and provide your doctor with a printout about the electrical activity of your heart before, during and after the stress test. Your heart beat is controlled by electrical impulses which tell the heart how fast to beat. This test will pick up on any irregular heart rhythm that occurs as the heart is stressed during exercise.
Echocardiograms show the actual structure of the heart and will detect any physical damage to the heart muscle, its walls or valves.
Scans Track Thallium Moving Through Your System
If you have an IV your doctor will inject thallium. The National Heart, Lung and Blood Institute states that thallium, which is a harmless radioactive material, will circulate through your body and enter the cardiac cells. Scans take images which show areas of the heart muscle that may not be receiving enough oxygen, indicating heart disease. These scans are taken during the test, right after exercise and often up to one hour after you have recovered.
