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.
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
electrocardiogram is done to:
- Help find the cause of unexplained chest
- 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
- Help find the cause of symptoms that occur during
exercise or activity, such as dizziness, fainting, or rapid, irregular
- Check for a blockage or
narrowing of an artery after a medical procedure, such as
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
- 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.
Experts disagree about the use of an exercise EKG to test
people who do not have symptoms of heart disease.
- Some experts think that anyone older than age
35 who is generally inactive should have an exercise test to screen for
"silent" heart disease before starting a vigorous exercise
- 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
- The U.S. Preventive Services Task Force recommends that exercise testing should not be done routinely for people who have a low risk of a heart attack or stroke.