A stress test, sometimes called a treadmill test or exercise test, helps a doctor find out how well your heart handles work. As your body works harder during the test, it requires more oxygen, so the heart must pump more blood. The test can show if the blood supply is reduced in the arteries that supply the heart. It also helps doctors know the kind and level of exercise appropriate for a patient.

A person taking the test

• is hooked up to equipment to monitor the heart.
• walks slowly in place on a treadmill. Then the speed is increased for a faster pace and the treadmill is tilted to produce the effect of going up a small hill.
• may be asked to breathe into a tube for a couple of minutes.
• can stop the test at any time if needed.
• afterwards will sit or lie down to have their heart and blood pressure checked.

Heart rate, breathing, blood pressure, electrocardiogram (e-lek"tro-KAR'de-o-gram) (ECG or EKG), and how tired you feel are monitored during the test.

Healthy people who take the test are at very little risk. It's about the same as if they walk fast or jog up a big hill. Medical professionals should be present in case something unusual happens during the test.

A physician may recommend an exercise stress test for various reasons:

• To diagnose coronary artery disease
• To diagnose a possible heart-related cause of symptoms such as chest pain, shortness of breath or lightheadedness
• To determine a safe level of exercise
• To check the effectiveness of procedures done to improve coronary artery circulation in patients with coronary artery disease
• To predict risk of dangerous heart-related conditions such as a heart attack.

Depending on the results of the exercise stress test, the physician may recommend more tests such as a nuclear stress test or cardiac catheterization.

Definition 

An exercise stress test is a screening tool to test the effect of exercise on your heart. The test gives a general sense of how healthy your heart is. See thallium and sestamibi stress tests.

How the test is performed 

You will walk or pedal on an exercise machine 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 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 preparation of the electrode sites on your chest may produce a mild burning or stinging sensation.

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 or pedaling a stationary bicycle. 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 Values 

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.

What the risks are  

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, but if it does, the patient is in the best position to receive medical attention.

Patients who are likely to have such complications are usually already known to have weak hearts, so they are not given this test.