The heart performs differently at rest than it does during exercise.
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An exercise stress test is designed to help your doctor learn how your heart performs during exercise or other activities that would make the heart work harder.�The term "stress" is used simply to distinguish the difference between a resting heart and a heart that is more actively pumping.�It is an investigation to measure the capacity of the heart, lungs and blood vessels to cope with the extra demands of exercise.�During a stress test, the patient is asked to exercise by running or cycling so that they put increased demand on their heart.�This increased demand may 'unmask' symptoms of angina or other heart disease that are not normally present at rest.
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The ability of the heart to cope with the extra stress is monitored using an ECG, or electrocardiogram, which looks at the electric activity of the heart.�As activity increases during the test, more oxygen is needed and the heart responds by pumping more blood.�This test can show if there is reduced blood flow to the arteries that supply the heart. It also helps doctors learn the limitations of exercise appropriate for each individual patient.

Why are Stress tests done?
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Stress tests are most commonly performed to help in the diagnosis of coronary heart disease.�Patients who have some symptoms of coronary heart disease (such as angina) but in whom the diagnosis is not certain might be asked to have a stress test to see how their heart copes with the extra stress of exercise.
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Stress tests may also be done to assess the prognosis (outlook) for patients with established coronary heart disease, to assess the effect of treatments like angioplasty on coronary heart disease symptoms, or after a heart attack to work out a safe exercise program.

What happens during the exercise stress test?

� Before the test begins, you will be connected up to monitors that measure your blood pressure and heart rhythm (ECG). A 'baseline' reading will be taken of your heart rhythm and blood pressure at rest. This allows the doctor to compare any changes that may occur with exercise.

• You will then be asked to walk or run on a treadmill (or sometimes ride an exercise bicycle) for a period of time. The intensity of the exercise will be increased as you go. The speed of the treadmill will be gradually increased and the incline will be increased to make it feel as though you are going up a small hill.
• Any changes that occur in your blood pressure or heart rhythm during the test will be recorded. Your pulse will also be closely monitored. For the test to be effective at detecting coronary artery disease, your heart rate must increase with the exercise to 85-90% of your predicted maximum possible heart rate.
• The test will be stopped if any concerning signs are noticed on the blood pressure or heart rhythm (ECG) monitors, or if you develop symptoms such as leg pain, chest pain, or breathlessness.�
• If you feel unwell at any time during the test, mention it immediately to the person in charge.�
• After the test is concluded, your blood pressure and heart rhythm will continue to be monitored as they return to normal.
• There's very little risk for healthy patients in taking the test - no more than if you were to walk fast or walk up stairs.

How to prepare for the test

• You must not eat, smoke, or drink beverages containing caffeine or alcohol for 3 hours before the test.�
• You should continue all medications unless instructed otherwise.�
• Wear comfortable shoes and loose clothing to allow exercise.

How will the test feel?

Electrodes (conductive patches) will be placed on your chest, arms, and