Stress or exercise electrocardiogram (EKG or ECG) is a test that checks for changes in the electrical activity of the heart during exercise. This test picks up some EKG abnormalities which are undetectable if you are at rest.

During a stress EKG, you may be required to either walk or be driven on a treadmill. A rest electrocardiogram is usually done before a stress EKG test and both results are compared to analyse and detect the heart condition you might be having.

How is a stress electrocardiogram done?

This test is usually done in a doctor’s office or a hospital laboratory by a technician or a doctor. The results are evaluated by your family doctor or cardiologist.

This test involves attaching small pads or patches of electrodes to certain parts of your arms, legs, ad chest. If these areas are hairy, they may need to be shaved.

These electrodes are hooked to a machine which then traces the electrical activity of your heart on a graph paper. Your blood pressure would be checked every few minutes during the test with a blood pressure cuff wrapped around your arm.

During the procedure, you either walk on a treadmill or pedal on a static bicycle while the EKG machine monitors your heart. However, before the stress test is done, the electrical activity of your heart at rest is monitored and traced on a graph paper.

The test is performed in three stages, each lasting three minutes. The speed of the treadmill or of that with which you pedal is increased in each stage.  During the test, the doctor or technician would asses what’s called the rating of perceived exertion by asking you to rate the stress of the exercise on a scale of 6 to 20.

The test is stopped whenever you think you have had enough, when your heart rate is at its highest, when your heart and lungs begin to manifest symptoms of stress such as chest pain and breathlessness, when the EKG shows that your heart muscle is not having enough blood, or if your blood pressure begins to plummet.

After the test, you can sit or lie down while your blood pressure is continually measured every 5 to 10 minutes, then the electrodes are removed. You would be instructed not to take a hot bath within an hour of undergoing the procedure to avoid the faintness that comes with doing that.

Why is a stress electrocardiogram done?

Doctors recommend a stress EKG to diagnose the cause of a patient’s unexplained chest pain, to diagnose the cause of faintness, difficulty breathing, and chest pain which a patient might experience during exercise, and to see how well medications are resolving a case of irregular heartbeat. It is also done to see how well people who have had a heart attack can tolerate exercise.

How does a stress electrocardiogram work?

The hearts four chambers contract and relax to pump and receive blood respectively in a rhythmic fashion controlled by the heart’s electrical activity. These movements of the heart occur in waves which are picked up by the electrodes attached to your body.

What risks are associated with a stress electrocardiogram?

Possible symptoms a patient undergoing a stress EKG may feel include faintness, irregular heartbeat, severe angina symptoms, and heart attack.

Patients who have angina which is not relieved by rest, heart attack, uncontrolled high blood pressure, life-threatening irregular heartbeat, severe lung diseases, or severe reduction in their red blood cells should not have a stress EKG.