You will begin your stress test by walking on a treadmill or pedaling a stationary bicycle. Every two to three minutes the speed or incline of the treadmill will gradually be increased. If you are out of shape or at a high risk for coronary artery disease, these increases will be smaller and more gradual. You will not be asked to exercise more than you are able to.
Your doctor will watch your heart's function and response to the physical activity closely, looking for any changes in your EKG pattern, blood pressure, and overall mental status. The exercise will be stopped if you have any chest pain or unusual shortness of breath while exercising or if you are clearly showing signs of heart disease. You will need to tell your doctor when you feel that you can only continue exercising for one more minute. This is because a radioactive tracer needs to be given through your IV one minute before the exercise is stopped. The tracer attaches to muscle cells in your heart, making them show up on the imaging camera. The exercise part of the test usually lasts a total of 8 to 12 minutes.
When you are finished exercising, you will be asked to lie down on the narrow imaging table and hold your left arm above your head. A large imaging camera will be brought close to your chest for a series of scans, or pictures. The healthy parts of your heart will appear to light up where they have absorbed the radioactive tracer and your heart will stay dark in the areas that may not be healthy. When the scanning is finished you will be able to leave the exam room to rest.
After two to four hours you will be asked to return. You will not need to exercise at this time. You will only need to lie down on the imaging table again while a second set of scans is taken of your heart at rest. These scans are then compared to those taken during the first scanning session while your heart was exercised. In certain situations you may be asked to return the next morning for a third set of scans.