Exercise Electrocardiogram

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.

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.

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.

An exercise electrocardiogram is done to:

Help find the cause of unexplained chest pain.
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.


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 severe narrowing of one of your heart valves (aortic valve stenosis).
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 called 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.