An exercise electrocardiogram (ECG) records your heart's response to the stress of exercise. An exercise ECG measures your heart's electrical activity, blood pressure and heart rate while you exercise, usually by walking on a treadmill.
It is usually done to pinpoint the cause of unexplained chest pain, especially if coronary artery disease (heart disease) is suspected. If you have been diagnosed with coronary artery disease, you may be given an exercise ECG to determine how far the disease has progressed and how much exercise you can do safely. If you have had a heart attack or heart surgery, it can help determine how much work or exercise you can do safely. It may also be recommended if you are experiencing irregular heartbeats (arrhythmia), very fast or slow heartbeats (tachycardia or bradycardia), palpitations (unusual throbbing or fluttering sensations in the heart), dizziness or excessive fatigue.
What to expect
An exercise ECG is usually done in a clinic or hospital. You will be asked to walk on a treadmill (or sometimes pedal a stationary bicycle). Small metal electrodes are attached to your chest, then you will either begin by walking slowly or pedalling. As you walk, a technician will monitor your heart's activity and rate, your breathing and blood pressure. Gradually the speed of the treadmill is increased so you have to walk more quickly. This will help your doctor see how your heart handles progressively greater challenges. The test continues until your heart is beating as fast as it safely can (you reach your peak exercise capacity, given your age and condition), or until you experience chest pain. It is generally a safe procedure, although it may trigger chest pain or irregular heart rhythms. Be sure to let someone know if you are feeling any discomfort or other symptoms. The length of time for the test is usually between 15 and 30 minutes.
How to prepare
Wear clothing and shoes that are comfortable for exercising. You'll probably be told not to eat for at least two hours before the test. If you're a smoker, you'll also need not to smoke for at least two hours before the test. Talk to your doctor about any medications you are taking. If you have questions, it is best to check with the centre where you are having your test for specific information about how to prepare.