What is a stress test?
A stress test lets doctors see how your heart works when it’s under stress, such as when you exercise. Many heart problems are easier for your doctor to find when your heart is working hard.
During an exercise tolerance (stress) test, the person walks at an increasingly rapid pace on a treadmill. The person wears a blood pressure cuff (the black arm band), which monitors blood pressure throughout the procedure. A video monitor displays the pulse and ECG. The results help determine the presence of coronary artery disease.
Video from Video Tape Library, Ltd.
Why would I need a stress test?
Most often, you'd have a stress test if you're having chest pain Chest Pain Chest pain is a very common complaint. Pain may be sharp or dull, although some people with a chest disorder describe their sensation as discomfort, tightness, pressure, gas, burning, or aching... read more . You might also need a stress test if you have a heart disorder and your doctor wants to see if it's getting worse.
How is a stress test done?
Small, round sensors (electrodes) are placed on your arms, legs, and chest to measure your heart’s electrical currents (called an electrocardiogram, or ECG Electrocardiography Electrocardiography is a test that measures your heart’s electrical activity. It's quick, painless, and harmless. The results of that test are shown in an electrocardiogram. It looks like a... read more
)You'll wear a blood pressure cuff on your arm
You'll walk on a treadmill or pedal on an exercise bike, picking up speed over time
As you exercise, doctors will watch your ECG and check your blood pressure often
If you can't exercise enough to do the test, doctors will give you a medicine to make your heart beat faster and stronger
Doctors will stop the test when:
Your heart rate nears the maximum recommended rate for your age
Your symptoms get too uncomfortable — you may have chest pain or feel like you can’t catch your breath
Your ECG or blood pressure readings show something abnormal
Sometimes instead of having an ECG during the stress test, you may have echocardiography Echocardiography and Other Ultrasound Procedures Echocardiography is also sometimes called an echocardiogram or an echo. An echo is an ultrasound of your heart. Sound waves bounce off your heart to create a moving image of your heart. This... read more 
or radionuclide imaging Radionuclide Scanning (Nuclear Scan) A radionuclide is a chemical that is radioactive. Doctors give you a small dose of the radionuclide. The radionuclide gives off radiation that's picked up by a scanner placed over a certain... read more . These tests also let your doctor see how your heart reacts to stress. These tests are more accurate but more expensive.
Are there any side effects to a stress test?
Usually you'll exercise hard enough to feel strain and puff for breath. If you have a heart problem, you might feel chest pain or become aware of your heart beats during the test. Although rare, you could have a heart attack Heart Attack A heart attack is when blood flow to part of your heart is suddenly blocked and some of your heart muscle dies. Go to an emergency department and chew on an aspirin tablet if you think you're... read more 
during the test. But your doctor will monitor you during the test to be ready for any problems.
What can my doctor learn from the stress test?
Stress tests help doctors:
Find signs of coronary artery disease Overview of Coronary Artery Disease (CAD) The heart is a muscle that pumps blood. Like all muscles, the heart needs a steady supply of blood to work. Blood that pumps through the heart doesn't feed the heart muscle. Instead the heart... read more
, which is when you have too little blood flow to your heartFigure out if you have a heart problem or lung problem, or if you’re just out of shape
