Medically reviewed by Drugs.com. Last updated on Dec 16, 2022.
A stress test shows how the heart works during physical activity. It also may be called a stress exercise test. Exercise makes the heart pump harder and faster. A stress test can show problems with blood flow within the heart.
A stress test usually involves walking on a treadmill or riding a stationary bike. A health care provider watches your heart rhythm, blood pressure and breathing during the test. People who can't exercise may be given a medicine that creates the effects of exercise.
Your health care provider may recommend a stress test if you have symptoms of coronary artery disease or an irregular heart rhythm, called an arrhythmia.
A stress test can help:
- Guide treatment decisions.
- Show how well heart treatment is working.
- Show how serious a heart condition is.
Why it's done
A health care provider may recommend a stress test to:
- Diagnose coronary artery disease. The coronary arteries are the major blood vessels that bring blood and oxygen to the heart. Coronary artery disease develops when these arteries get damaged or diseased. Cholesterol deposits in the heart arteries and inflammation usually cause coronary artery disease.
- Diagnose heart rhythm problems. A heart rhythm problem is called an arrhythmia. An arrhythmia can cause the heart to beat too fast or too slowly.
- Guide treatment of heart disorders. If you've already been diagnosed with a heart condition, an exercise stress test can help your provider know if your treatment is working. The test results also help your provider decide on the best treatment for you.
- Check the heart before surgery. A stress test can help show if surgery, such as a valve replacement or a heart transplant, might be a safe treatment.
If an exercise stress test doesn't show the cause of symptoms, your provider may recommend a stress test with imaging. Such tests include a nuclear stress test or stress test with an echocardiogram.
A stress test is generally safe. Complications are rare. Possible complications of an exercise stress test are:
- Low blood pressure. Blood pressure may drop during or right after exercise. The drop might cause dizziness or fainting. The problem will likely go away after the exercise stops.
- Irregular heart rhythms, called arrhythmias. Arrhythmias that occur during an exercise stress test usually go away soon after the exercise stops.
- Heart attack, also called myocardial infarction. Although very rare, it's possible that an exercise stress test could cause a heart attack.
How you prepare
Your health care provider can tell you how to prepare for your stress test.
Food and medicine
You may be asked not to eat, drink or smoke for a time before a stress test. You may need to stay away from caffeine the day before and the day of the test.
Some medicines might have an effect on stress tests. Ask your health care provider if you can take your medicines before the test.
If you use an inhaler for asthma or other breathing problems, bring it to the test. Tell your health care providers that you use an inhaler.
Clothing and personal items
Wear or bring comfortable clothes and walking shoes.
What you can expect
A stress test usually takes about an hour, including the prep time and the time it takes to do the actual test. The exercise part takes only around 15 minutes. It usually involves walking on a treadmill or pedaling a stationary bicycle. If you can't exercise, you'll receive medicine through an IV. The medicine creates the effect of exercise on the heart.
Before a stress test
Your health care provider usually asks questions about your medical history and how often and how hard you exercise. This helps the provider decide how much you can exercise during the test. Your provider usually listens to your heart and lungs to check for any issues that might affect your test results.
During a stress test
A health care provider puts sticky patches called electrodes on your chest and sometimes the arms and legs. Body hair may be shaved to help the patches stick. The patches record the heart's rhythm. Wires connect the patches to a computer, which shows or prints the test results. This part of a test is called an electrocardiogram, commonly called an ECG.
A cuff on your arm checks your blood pressure during the test. You may be asked to breathe into a tube during the test to show how well you're able to breathe during exercise.
Exercise may be on a treadmill or stationary bike. The pace is easy at first. As the test continues, the exercise gets harder. You can use the railing on the treadmill for balance. Don't hang on tightly, as this may affect the results.
Exercise continues until your heart rate reaches a target level. You might need to stop sooner if you develop symptoms such as:
- Moderate to severe chest pain.
- Severe shortness of breath.
- Unusually high or low blood pressure.
- An irregular heart rhythm.
If you can't exercise during the stress test, a health care provider gives you medicine by IV. The medicine increases blood flow to the heart. You might feel flushed or short of breath, just as you would if you were exercising. You might get a headache.
You can stop the test anytime you're too uncomfortable. Your care provider might stop the test if there are concerns about the way your heart is acting during the test.
After a stress test
After exercising, you may be asked to stand still for several seconds and then lie down for a while. Your care provider watches for problems as your heart rate and breathing recover from the exercise.
When the test is done, you may return to your usual activities unless your provider tells you otherwise.
In an exercise stress test, sticky patches called electrodes are placed on the chest and sometimes the arms and legs. They record the heart's rhythm. A health care provider checks the heartbeat while the person walks on a treadmill or pedals a stationary bike.
Stress test results helps your health care provider plan or change your treatment. If the test shows that your heart is working well, you may not need more tests.
If the test suggests you might have coronary artery disease, you may need a test called a coronary angiogram. This test helps health care providers see blockages in the heart arteries.
If the test results are OK but your symptoms get worse, your care provider might recommend more testing. Tests may include a nuclear stress test or a stress test that includes an echocardiogram. These tests give more details about how the heart works.