Illness and Conditions - Medical Tests
An exercise electrocardiogram (EKG or ECG) is a test that checks for changes in your heart while you exercise. Sometimes EKG abnormalities can be seen only during exercise or while symptoms are present. This test is sometimes called a "stress test" or a "treadmill test." During an exercise EKG, you may either walk on a motor-driven treadmill or pedal a stationary bicycle.
The heart is a muscular pump made up of four chambers . The two upper chambers are called atria, and the two lower chambers are called ventricles. A natural electrical system causes the heart muscle to contract and pump blood through the heart to the lungs and the rest of the body. See a picture of the heart and its electrical system .
An exercise EKG translates the heart's electrical activity into line tracings on paper. The spikes and dips in the line tracings are called waves. See a picture of the EKG components and intervals .
A resting EKG is always done before an exercise EKG test, and results of the resting EKG are compared to the results of the exercise EKG. A resting EKG may also show a heart problem that would make an exercise EKG unsafe.
Why It Is Done
An exercise electrocardiogram is done to:
Exercise electrocardiograms are not recommended if you're healthy and have no symptoms of heart disease. 1
How To Prepare
Tell your doctor if you:
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form (What is a PDF document?) .
Your doctor may recommend how you should eat before the test. For example, your doctor may suggest you only eat a light breakfast before your test.
An exercise EKG may be dangerous and should not be done in some situations. Be sure to tell your doctor if you:
Remove all jewelry from your neck, arms, and wrists. Wear flat, comfortable shoes (no bedroom slippers) and loose, lightweight shorts or sweat pants. Men are usually bare-chested during the test. Women often wear a bra, T-shirt, or hospital gown. Avoid wearing any restrictive clothing other than a bra.
You may want to stretch your arm and leg muscles before beginning an exercise EKG.
How It Is Done
An exercise electrocardiogram (EKG or ECG) is usually done in a doctor's office, clinic, or hospital lab by a health professional or doctor. The test results are evaluated by an internist , family medicine doctor , or cardiologist .
Before the test
During the test
For exercise, you typically either walk on a treadmill or pedal on a stationary bicycle while being monitored by an EKG machine. Your EKG will be monitored on screen, and paper copies will be printed out for later review before you start the exercise, at the end of each section of exercise, and while you are recovering.
The test is usually performed in a series of stages, each lasting 3 minutes. After each 3-minute stage, the resistance or speed of the treadmill or bicycle is increased.
After the test
When the exercise phase is completed:
The entire test usually takes 15 to 30 minutes.
How It Feels
The electrodes may feel cool when they are put on your chest. If you have a lot of hair on your chest, a small area under each electrode may need to be shaved. When the electrodes are taken off, they may pull your skin a little.
The room where the exercise electrocardiogram is done may be kept cool for comfort, since you will warm up rapidly when you begin to exercise.
The blood pressure cuff on your arm will be inflated every few minutes. This will squeeze your arm and feel tight. Tell your health professional if this is painful.
While exercising, you may have leg cramps or soreness; feel tired, short of breath, or lightheaded; have a dry mouth; and sweat. You might even have some mild chest pain. Tell the health professional or doctor if you have these symptoms.
An exercise electrocardiogram is generally safe. Emergency equipment will be available in the testing area. Risks include:
The electrodes are used to transfer an image of the electrical activity of your heart to tracing on paper. No electricity passes through your body from the machine, and there is no danger of getting an electrical shock.
An exercise electrocardiogram (EKG or ECG) is a test that checks for changes in your heart while you exercise. Your doctor may be able to talk to you about your results right after the test. But complete test results may take several days.
Your doctor will look at the pattern of spikes and dips on your electrocardiogram to check the electrical activity in different parts of your heart. The spikes and dips are grouped into different sections that show how your heart is working. See a picture that explains the EKG components and intervals .
What Affects the Test
You may not be able to have the test or the results may not be accurate if:
What To Think About
An exercise EKG is not always accurate. The test results from an exercise EKG are always evaluated along with other information, such as your symptoms and other risk factors.
Other Places To Get Help
Last Revised: September 11, 2012
Author: Healthwise Staff
U.S. Preventive Services Task Force (2004). Screening for coronary heart disease: Recommendation statement. Annals of Internal Medicine, 140(7): 569–572. Also available online: http://www.uspreventiveservicestaskforce.org/uspstf/uspsacad.htm.
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