An exercise stress test is used to determine how well your heart responds during times when it’s working its hardest.
During the test, you’ll be asked to exercise — typically on a treadmill — while you’re hooked up to an electrocardiogram (EKG) machine. This allows your doctor to monitor your heart rate.
The exercise stress test is also referred to as an exercise test or treadmill test.
An exercise stress test is primarily used to help your doctor determine if your heart receives enough oxygen and proper blood flow when it needs it most, such as when you are exercising.
It can be ordered for people who have been experiencing chest pains or other symptoms of coronary heart disease (also called coronary artery disease).
An exercise stress test may also be used to help determine your level of health, especially if you are starting a new exercise program. This allows your doctor to learn what level of exercise you can safely handle.
If you are a smoker over 40 years old, or if you have other risk factors for heart disease, you should talk to your doctor to see if an exercise stress test is right for you.
Stress tests are generally considered safe, especially since they’re done in a controlled environment under the supervision of a trained medical professional.
However, there are some rare risks, such as:
- chest pain
- collapsing
- fainting
- heart attack
- irregular heartbeat
However, your risk of experiencing these reactions during the test is low, since your doctor will screen you for problems beforehand. People who are at higher risk of these complications — such as those with advanced coronary heart disease — are rarely asked to do the test.
Prior to your test, your doctor will perform a physical exam and ask about your complete medical history. At this point, tell your doctor about your symptoms, especially any chest pains or shortness of breath.
You should also tell your doctor about any conditions or symptoms that may make exercising difficult, such as stiff joints from arthritis.
Finally, let your doctor know if you have diabetes, because exercise affects blood sugar. If you do have diabetes, your doctor may want to monitor your blood glucose levels during the exercise test as well.
Your doctor will give you complete instructions about how to prepare.
Food and medications
Your doctor may instruct you to avoid eating or drinking caffeinated beverages for 3 hours before the test. You should also avoid smoking.
You should only stop taking medications before the test if your doctor tells you to do so.
Clothing and personal items
On the day of the test, be sure to dress in loose, comfortable clothing. Something that is light and breathable is best.
Make sure to wear comfortable shoes, such as sneakers.
You’ll start off by walking slowly on a treadmill. The speed and grade of the treadmill will be increased as the test continues.
If you experience any difficulties — especially, chest pains, weakness, or fatigue — you may ask to stop the test.
When your doctor is satisfied with your results, you’ll be able to stop exercising. Your heart rate and breathing will continue to be monitored for a short while afterward.
Types of tests
There are three types of stress tests:
- Exercise stress test. This is also called a treadmill test. You’ll walk in place on a treadmill while you’re hooked up to an electrocardiogram (EKG) machine that monitors your heart.
- Nuclear stress test. This is also called a thallium stress test. It’s the same as an exercise stress test, but you will receive dye via an intravenous line (IV) inserted in your arm. This allows your healthcare professional to view images of your heart using a special camera.
- Stress echocardiogram. This is the same as an exercise stress test, but your healthcare professional will also hold a transducer against your chest. This wand-like device creates sound waves that make moving pictures of your heart.
Before a stress test
Report any chest pains or other complications you notice on the day of the test.
Before you begin exercising, you’ll be hooked up to the EKG machine. Several sticky pads will be attached to your skin under your clothes.
Your doctor or nurse will check your heart rate and breathing before you begin exercising. Your doctor may also have you breathe into a tube to test the strength of your lungs.
After a stress test
After the test, you’ll be given water and asked to rest. If your blood pressure rises during the test, your attending nurse may continue to monitor your blood pressure.
A few days after the test, your doctor will review the results with you. The test could reveal irregular heart rhythms or other symptoms that indicate coronary artery disease, such as blocked arteries.
If your doctor determines you may have coronary artery disease or other heart problems, they may begin treatments or order more tests, such as a nuclear stress test.
A stress test can estimate your risk of having heart disease. A doctor or trained technician performs the test. They’ll learn how much your heart can manage before an abnormal rhythm starts or blood flow to your heart muscle drops.
There are different types of stress tests. The exercise stress test -- also known as an exercise electrocardiogram, treadmill test, graded exercise test, or stress EKG -- is used most often. It lets your doctor know how your heart responds to being pushed. You’ll walk on a treadmill or pedal a stationary bike. It’ll get more difficult as you go. Your electrocardiogram, heart rate, and blood pressure will be tracked throughout.
Your doctor uses the test to:
- Don’t eat or drink anything except water for 4 hours before the test.
- Don’t drink or eat anything with caffeine for 12 hours before the test.
- Don’t take the following heart medications on the day of your test, unless your doctor tells you otherwise or the medication is needed to treat chest discomfort the day of the test:
- If you use an inhaler for your breathing, bring it to the test.
You may also be asked to stop taking other heart drugs on the day of your test. If you have questions about your meds, ask your doctor. Don’t discontinue any drug without checking with them first.
First, a technician will gently clean several small areas on your chest and place small, flat, sticky patches called electrodes on them. They’ll be attached to an electrocardiogram monitor -- called an EKG -- that charts your heart's electrical activity during the test.
Before you start exercising, the technician will perform an EKG to measure your heart rate at rest. They’ll also take your blood pressure.
You will begin to exercise by walking on a treadmill or pedaling a stationary bicycle. The rate of exercise or degree of difficulty will gradually increase. You will be asked to exercise until you feel exhausted. If medication is used, or it is a nuclear stress test, an IV will be inserted in your arm in order to have the medication administered.
At regular intervals, the lab personnel will ask how you are feeling. Tell them if you feel:
- Chest or arm discomfort
- Short of breath
- Dizzy
- Lightheaded
- Any other unusual symptoms
It’s normal for your heart rate, blood pressure, breathing rate, and perspiration to increase during the test. The lab personnel will watch for anything on the EKG monitor that suggests the test should be stopped.
After the test, you’ll walk or pedal slowly for a couple of minutes to cool down. Your heart rate, blood pressure, and EKG will continue to be monitored until the levels begin returning to normal.
Although the appointment lasts about 60 minutes, the exercise time is usually between 7 and 12 minutes.
Ask your doctor if you have any questions about the exercise stress test.
Dobutamine or adenosine stress test: This is for people unable to exercise. You’ll take a drug to make the heart respond as if you were exercising. This way, the doctor can still determine if there are blockages in the arteries.
Stress echocardiogram: An echocardiogram (often called "echo") is a graphic outline of the heart's movement. A stress echo can accurately visualize the motion of the heart's walls and pumping action when the heart is stressed; it may reveal a lack of blood flow that isn't always apparent on other heart tests.
Nuclear stress test: This helps figure out which parts of the heart are not working well. A small amount of radioactive substance will be injected into you. Your doctor will use a special camera to see rays emitted from the substance in your body. This will give them clear pictures of the heart tissue on a monitor. These pictures are done at rest and after exercise. Your doctor will be able to spot areas of your heart that aren’t getting enough blood. The test could last to up to 4 hours to allow enough time for the radioactive substance to flow through your body.
How you’ll prepare for these stress tests will vary. Ask your doctor about any specific instructions.
If you take insulin to control your blood sugar, ask your doctor how much you should take the day of the test. Often, you’ll take only half of your usual morning dose and eat a light meal 4 hours before.
If you take pills to control your blood sugar, don’t take your medication until after the test is over.
Don’t take your diabetes medication but skip a meal before the test.
If you have a glucose monitor, bring it with you. You’ll want to check your blood sugar levels before and after your exercise stress test. If you think that your blood sugar is low, tell the lab personnel right away.
Plan to eat and take your blood sugar medication after your stress test.
Wear soft-soled shoes suitable for walking and comfortable clothes. Don’t bring valuables.