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.
Help decide on the best treatment for a person with angina.
See how well people who
have had a
heart attack or heart surgery are able to tolerate
exercise.
Help find the cause of symptoms that occur during
exercise or activity, such as dizziness, fainting, or rapid, irregular
heartbeats (palpitations).
Check for a blockage or
narrowing of an artery after a medical procedure, such as
angioplasty or
coronary artery bypass surgery, especially if the
person has chest pain or other symptoms.
See how well medicine or
other treatment for chest pain or an irregular heartbeat is
working.
Help you make decisions about starting an exercise program
if you have been inactive for a number of years and have an increased chance of
having heart disease.
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:
Are taking any medicines, including a medicine
for an erection problem (such as Viagra). You may need to take nitroglycerin
during this test, which can cause a serious reaction if you have taken a
medicine for an erection problem within the previous 48 hours. Ask your doctor
whether you need to stop taking any of your other medicines before the
test.
Are allergic to any medicines, such as those used to numb the
skin (anesthetics).
Have had bleeding problems
or take blood-thinners, such as aspirin or warfarin (such as
Coumadin).
Have joint problems in your hips or legs that may make
it hard for you to exercise.
Are or might be pregnant.
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:
Think you are having a heart
attack.
Are having chest pain that is not relieved with rest (unstable angina).
Have high blood pressure
that is not controlled with medicine.
Have untreated,
life-threatening irregular heart rhythms (arrhythmias).
Have an infection in your heart muscle
(myocarditis).
Have a severe decrease in the amount of red blood
cells (anemia).
Have a stretched and bulging
section in the wall of the large artery that carries blood from the heart
(aortic aneurysm) or in one of the chambers of the
heart (ventricular aneurysm).
Have severe lung disease.
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
Areas on your arms, legs, and chest where
small metal discs (electrodes) will be placed are cleaned and may be shaved to
provide a clean, smooth surface to attach the discs. A special EKG paste or
small pads soaked in alcohol may be placed between the discs and your skin to
improve conduction of the electrical impulses, but in many cases disposable
discs are used that do not require paste or alcohol.
The electrodes
are hooked to a machine that traces your heart activity onto a piece of paper.
Your chest may be loosely wrapped with an elastic band to keep the electrodes
from falling off during exercise. A blood pressure cuff will be wrapped around
your upper arm so that your blood pressure can be checked every few minutes
during 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.
For the treadmill test, the treadmill will move slowly in a level or slightly inclined
position. As the test progresses, the speed and steepness of the treadmill will
be increased so that you will be walking faster and at a greater
incline.
For the stationary bicycle, you
will sit on the bicycle with the seat and handlebars adjusted so that you can
pedal comfortably. You can use the handlebars to help you balance, but you
should not use them to support your weight. You will be asked to pedal fast
enough to maintain a certain speed. The resistance will then be gradually
increased, making it harder to pedal.
In both the treadmill and the bicycle tests, your EKG, heart
rate, and blood pressure will be recorded during the exercise. Your heart rate
and EKG will be recorded continuously. Your blood pressure is usually measured
during the second minute of each stage. It may be measured more frequently if
the readings are too high or too low. During the test, you might be asked to give a number that answers the question "How hard do you feel the exercise is?" The number will be on a scale from 6 to 20 and is a rating of perceived exertion.
The test continues until you
need to stop, until you reach your maximum heart rate, until you begin to show
symptoms of stress on your heart and lungs (such as fatigue, extreme shortness
of breath, or angina), or until the EKG tracing shows decreased blood flow to
your heart muscle.
The test may also be stopped if you develop
serious irregular heartbeats or if your blood pressure drops below your resting
level.
After the test
When the exercise phase is
completed:
You will be able to sit or lie down and rest.
Your EKG and blood pressure will be checked for about 5 to 10
minutes during this time.
The electrodes are then removed from your
chest, and you may resume your normal activities.
Do not take a hot
bath or shower for at least an hour, since hot water after vigorous exercise
can make you feel dizzy and faint.
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.
Risks
An exercise electrocardiogram is generally
safe. Emergency equipment will be available in the testing area. Risks
include:
Irregular heartbeats during the
test.
Severe chest pain
(angina).
Fainting.
Falling.
Heart
attack.
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.
Results
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.
Exercise electrocardiogram (EKG or ECG) results
Normal:
You reach your target heart rate (based on
your age) and can exercise without chest pain or other symptoms of heart
disease.
Your blood pressure increases steadily
during exercise.
Your EKG tracings do not show any
significant changes. Your heartbeats look normal.
Abnormal:
You have chest pain during or right after
the test.
You have other symptoms of heart disease,
such as dizziness, fainting, or extreme shortness of breath.
Your blood pressure drops or does not rise
during exercise.
The EKG tracing does not look normal.
Your heartbeats are too fast, too slow, or
very irregular.
What Affects the Test
You may not be able to have the
test or the results may not be accurate if:
The electrodes are not securely attached to the
skin.
You are not able to exercise hard enough during the test.
You take certain medicines, such as digoxin, phenothiazines,
and some antiarrhythmic medicines.
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.
Some people who have a normal exercise
electrocardiogram test may still have heart disease, and some people with an
abnormal test do not have heart disease. Because heart disease is rare in younger people who do not
have symptoms, an exercise EKG may not be accurate. A falsely abnormal result
(false-positive) may cause needless worry and further
unnecessary testing.
The test is less accurate
in young or middle-aged women who do not have typical symptoms of heart
disease.
Sometimes doctors automatically schedule routine tests because they think that's what patients expect. But experts say routine heart tests can be a waste of time and money. For more information, see Heart Tests: When Do You Need Them?
Further tests, such as cardiac perfusion scanning, stress
echocardiogram, or cardiac catheterization, may be needed to further evaluate
an abnormal exercise EKG test result. For more information, see the topics
Echocardiogram,
Cardiac Perfusion Scan, and
Cardiac Catheterization.
Other Places To Get Help
Organizations
American Heart Association (AHA)
7272 Greenville Avenue
Dallas, TX 75231
Phone:
1-800-AHA-USA1 (1-800-242-8721)
Web Address:
www.heart.org
Visit the American Heart Association (AHA) website for information on
physical activity, diet, and various heart-related conditions. You can search for information on heart disease and stroke, share information with friends and family, and use tools to help you make heart-healthy goals and plans. Contact the AHA to find your
nearest local or state AHA group. The AHA provides brochures and information
about support groups and community programs, including Mended Hearts, a
nationwide organization whose members visit people with heart problems and
provide information and support.
National Heart, Lung, and Blood Institute
(NHLBI)
P.O. Box 30105
Bethesda, MD 20824-0105
Phone:
(301) 592-8573
Fax:
(240) 629-3246
TDD:
(240) 629-3255
Email:
nhlbiinfo@nhlbi.nih.gov
Web Address:
www.nhlbi.nih.gov
The U.S. National Heart, Lung, and Blood Institute
(NHLBI) information center offers information and publications about preventing
and treating:
Diseases affecting the heart and circulation, such as heart
attacks, high cholesterol, high blood pressure, peripheral artery disease, and
heart problems present at birth (congenital heart diseases).
Diseases that affect the lungs, such as asthma, chronic
obstructive pulmonary disease (COPD), emphysema, sleep apnea, and
pneumonia.
Diseases that affect the blood, such as anemia,
hemochromatosis, hemophilia, thalassemia, and von Willebrand disease.
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.
Other Works Consulted
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis:
Saunders.
Chou R, et al. (2011). Screening asymptomatic adults with resting or exercise electrocardiography: A review of the evidence for the U.S. Preventive Services Task Force. Annals of Internal Medicine, 155(6): 375–385.
Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
Gibbons RJ, et al. (2002). ACC/AHA 2002 guideline update for exercise testing: Summary article. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1997 Exercise Testing Guidelines). Circulation, 106(14): 1883–1892.
Lauer M, et al. (2005). Exercise testing in asymptomatic adults. A statement for professionals from the American Heart Association Council on Clinical Cardiology, Subcommitee on Exercise, Cardiac Rehabilitation, and Prevention. Circulation, 112(5): 771–776.
Myers J, et al. (2009). Recommendations for clinical exercise laboratories. A scientific statement from the American Heart Association. Circulation, 119(24): 3144–3161.
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.
Credits
By
Healthwise Staff
Primary Medical Reviewer
Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology
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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