A stress test is a medical examination performed to evaluate arterial blood flow to the myocardium (heart muscle) during physical exercise, compared to blood flow while at rest. As an exercise test, the results can also reflect overall physical fitness. These tests do not assess emotional stress or other connotations of the term.

You will walk on a treadmill while the electrical activity of your heart is measured with an electrocardiogram (ECG), and blood pressure readings are taken. This will measure your heart's reaction to your body's increased need for oxygen.

The test continues until you reach a target heart rate, unless complications such as chest pain or an exaggerated rise in blood pressure develop. You will continue to be monitored for 10 - 15 minutes after exercising, or until your heart rate returns to baseline.

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 for exercise.

Tell your doctor if you are taking sildenafil citrate (Viagra) and have taken a dose within the past 24 hours. This is necessary because nitroglycerin, which is sometimes given during a stress test to relieve chest pain, should not be given to a person who has recently taken Viagra, since the combination can cause a serious drop in blood pressure.

How the Test Will Feel

Electrodes (conductive patches) will be placed on your chest, arms, and legs to record the heart's activity.

The blood pressure cuff on your arm will be inflated every few minutes, producing a squeezing sensation that may feel tight. Baseline measurements of heart rate and blood pressure will be taken before exercise starts.

You will start walking on a treadmill. The pace and incline of the treadmill will gradually be increased.

Rarely, people experience chest discomfort, palpitations, dizziness, or shortness of breath during the test.

Why the Test is Performed

A stress test is performed to determine causes of chest pain, the exercise capacity of the heart, appropriate exercise levels in those beginning an exercise program, and to identify rhythm disturbances during exercise. There may be additional reasons that your health care provider requests this test.

Normal Results

Normally, heart rate increases in proportion to the workload and attains endurance levels appropriate for age and conditioning level.

What Abnormal Results Mean

Abnormal results may indicate arrhythmias during exercise, stress on the heart provoked by exercise, possible coronary artery disease (blockage in the arteries), or lack of aerobic fitness.

Risks

Stress tests are generally safe. Some patients may have chest pain or may faint or collapse. A heart attack or dangerous irregular rhythm rarely occurs. Persons who are likely to have such complications are usually already known to have weak hearts, so they are not given this test.