What Does an Exercise Stress Test Show?

An exercise stress test (treadmill test/exercise test/stress test) helps your doctor to find how well your heart works during physical activity. As exercise makes your heart work harder and pump faster, an exercise stress test may reveal problems with blood flow within your heart. It involves walking on a treadmill or riding a stationary bike till you achieve a particular heart rate and monitoring of your heart rhythm, blood pressure, and breathing during these activities. Sometimes, you may receive a drug that imitates the effects of exercise and the parameters may be measured.

As your body works harder during the test, it requires more oxygen; therefore, your heart must pump more blood. This test may predict and determine if the blood supply in the arteries that supply your heart is reduced. Additionally, this test is performed to determine what intensity and what type of exercise or physical activity is appropriate for you. Your electrocardiogram (ECG), heart rate, and blood pressure are monitored throughout.

There are different types of this test:

• Exercise stress test or exercise electrocardiogram
• Treadmill test
• Graded exercise test
• Stress electrocardiogram (EKG/ECG)

• Avoid eating or drinking anything except water for four hours before your test.
• Avoid drinking coffee for 12 hours before the test.
• Wear comfortable, loose-fitting clothes and walking shoes with rubber soles or sport shoes.
• Do not take certain heart medications on the day of your test unless your doctor/cardiologist advises you, especially beta-blockers (metoprolol, bisoprolol, and atenolol)
• If you use an inhaler for your breathing, carry it during the test.
• If you have any questions or doubts about your medications, ask your doctor/cardiologist (heart specialist).
• Do not stop taking any of your prescribed drugs without consulting with your doctor/cardiologist.
• Inform your doctor if you are consuming any over-the-counter medicines, herbal products, or vitamins. Your doctor may inform you to stop taking them before the test.

Before the test:

A technician will gently clean 10 small areas on your chest and place small, sticky patches (electrodes). These patches will be attached to an electrocardiogram (ECG) monitor that charts your heart’s electrical activity during the test.

The equipment used during these tests are as follows:

• An electrocardiography (ECG) machine to record your heartbeat and heart waves
• Wires or electrodes hooked up to your chest, arms, or shoulders and connected to the ECG machine
• A mouthpiece attached at the end that measures the air you breathe out

During the test:

When you are hooked up to an EKG machine, a doctor or trained technician will ask you to run typically on a treadmill. This allows your doctor to monitor your heart rate and ECG changes. The test may take 20-30 minutes depending upon the heart rate you are required to achieve during the test. The target heart rate depends on your age and weight. As you run, every three minutes, the slope and speed of the treadmill increases gradually. You have to run until you achieve the target or you feel fatigued, breathlessness or chest pain.

You will be

• Hooked up to an EKG machine to monitor your heart.
• Informed to walk slowly in place on a treadmill. Then the speed will be increased for a faster pace. It tilts so you feel like you are walking up a small hill.
• Asked to breathe into a tube for a couple of minutes.
• Informed that you can stop the test at any time you need to.
• Asked to sit or lie down after slowing down for a few minutes, and your heart rate and blood pressure will be checked.

Healthy people who take this test are at very little or no risk. It’s about the same as if they walk fast or jogs up on a hill. However, a medical professional should be present to monitor you during the test, in case something unusual happens.