The exercise stress test, also called the exercise tolerance or treadmill test, helps your cardiologist determine whether your heart gets sufficient oxygen and blood flow during hard work. These exercise tests are the preferred method for diagnosing and detecting potential risk factors for heart disease, say specialists on the Harvard Health Letter website.
Who Needs the Test?
Your doctor may order an exercise tolerance test if you have symptoms of or show significant risk factors for coronary artery disease. Patients with unexplained shortness of breath and fatigue, irregular heart beat, borderline hypertension and people over 40 who smoke, have high cholesterol and a history of family heart disease are also candidates.
How it Works
You may have a normal resting echocardiogram, but exercise stress may unmask symptoms of heart disease, explain heart specialists on Heartsite.com. Healthy coronary arteries dilate during exercise. Blocked arteries do not. These narrow arteries restrict blood flow to the heart, causing chest discomfort and shortness of breath. The electrocardiogram readings performed during the test will indicate this restricted blood flow.
Taking the Test
The test begins with a blood pressure and heart rate test at rest. Then, the cardiologist attaches electrodes to your chest, shoulder and hips, and connects them to the EKG machine. After you are hooked up, the cardiologist will ask you to begin walking at a moderate pace. The pace and incline may increase at three-minute intervals. Some cardiologists may ask you to breathe into a tube at certain points during the test. The test usually stops when you reach a pulse rate of 85 percent of your maximum heart rate, determined by subtracting your age from 220, but the cardiologist may stop the test if you show unsteady gait, dizziness or shortness of breath.
Preparation
Prevent nausea by avoiding meals for at least three hours before the treadmill test. Diabetics are the exception to this rule. If you are diabetic, bring your glucose monitor and test your blood sugar level before taking the exercise tolerance test. If it's low, have a small snack before testing. Wear comfortable workout shoes and exercise clothing. Your doctor may tell you to avoid taking certain medications prior to taking the treadmill test.
