What is a treadmill stress test?
This is an exercise test used to evaluate how your heart responds to the physical stress. This is accomplished by having you walk on a treadmill, the speed and inclination of which is gradually increased, while your electrocardiogram (ECG) and blood pressure are continuously monitored.
Exercise stress testing is tremendously informative in screening for coronary artery disease as well as periodically following known heart disease. This test is usually ordered for patients who are experiencing symptoms of chest discomfort, shortness of breath or palpitations (irregular heart beat). Often these symptoms are related to physical activity. As the body works harder during the test, it requires more oxygen to meet the increased metabolic demands of exercise. The ECG is monitored continuously during the test to watch for any changes that suggest ischemia– an insufficient delivery of oxygen to the working heart muscle. It also provides information regarding your level of physical fitness and can be used to try and bring out any heart rhythm disturbances.
Pre- Exercise Test, please follow these instructions:
- Do not eat or drink two hours prior to your treadmill, however, you may brush your teeth and have small sips of water. A full stomach may lead to nausea during exercise.
- Do not have any caffeine for at least 3-4 hours prior to your test. Coffee, tea, soft drinks and chocolate may contain caffeine.
- Do not smoke prior to your test.
- A shower or bath should be taken prior to the test in order to allow good skin contact with the electrodes. Do not use lotion.
- Wear walking shoes and comfortable clothing on the day of the test. Do not wear boots, high-heeled shoes or slippers.
- Physically and mentally relax before your test; no strenuous exercise should be performed.
- Bring the medications you are currently taking and have your morning doses unless specifically instructed by doctor to stop any medications prior to the test.
- Insulin dependent Diabetic Instructions: For morning treadmill do not take the morning insulin dose and have a light breakfast.
How is the test performed?
- You must have heard of mishaps that have occurred just after or during a stress test. It is therefore essential that a brief history and examination be taken so as to make sure that you are fit to undergo the test.
- The test is then explained to you. Once this is completed you will be asked to read and sign a consent form. The staff will answer any questions relating to the consent form.
- The technician will then prepare the skin so the ECG can monitor your heart rhythm throughout the test without interference from motion and sweat. For men this involves shaving the skin, rubbing it vigorously with alcohol and then gently roughening the skin with special abrasive paper. For women the skin still has to be rubbed with alcohol and also gently roughed. Ten electrodes are then applied to the chest.
- During your stress test there is always an experienced Physician immediately available. All the necessary resuscitation equipment and emergency medications are readily available.
- Before the test your blood pressure and ECG will be recorded in the sitting and standing position.
- Then the actual walk on treadmill is begun. Initially the treadmill will be flat and moving very slowly. During the test, you will be asked how you are feeling and your blood pressure will be recorded every 3 minutes. Your ECG is monitored continuously and taken every 3 minutes as a permanent record print. The speed and inclination of the treadmill will progressively increase every 3 minutes as the test progresses.
- The test is a heart rate limited and symptom limited test. The target heart rate is 85% of your maximum predicted heart rate (220-Age in years). The test will stop if you develop symptoms or if you achieve the target heart rate, whichever occurs first. The test will also be stopped if you ask to stop the test or if the doctor stops the test because of changes in the ECG or blood pressure.
- During the test, be sure to inform if you have any of the following:
- chest, arm, throat or jaw discomfort
- shortness of breath
- dizziness or light-headedness
- leg cramps or soreness
- At the completion of the test your clinical condition, blood pressure and ECG will be monitored until everything returns to baseline.
What are the instructions after the Regular Treadmill Stress Test:
- You may resume your normal activity unless otherwise directed by the testing physician.
- Take your regular medications as directed unless otherwise directed by the testing physician.
- Keep any scheduled follow-up appointments.
The final report of the exercise stress test will be given to the patient on the same day within 15-20 minutes.
Is there any risk involved?
The risk of the treadmill is very small and is equivalent to the risk of a similar degree of exercise experienced by the person’s daily life. The careful monitoring of the heart, his/her blood pressure and the continuous ECG record, all serve to further minimize the small risk of the test.
It has obvious advantages over other tests that turned it into the first line test to give a useful overview for almost every cardiac disease:
- it is not expensive
- it’s the most physiologic way to test the heart
- it imitates every-day stress realistically
- it can be repeated as often as necessary without imposing health risks on the patient due to x-rays, drugs, or risks associated with invasive procedures