In general, the only preparation needed the day before a stress test is to stop taking certain heart medications if requested by the doctor, says Heartsite.com. The day of the test, the doctor may ask the patient to avoid eating or drinking at least three hours before the test.
A stress test is usually called for in patients with symptoms of, or risk factors for, coronary artery disease, reports Heartsite.com. Patients with this disease may not have abnormal EKG results while at rest, but these results may change during a stress test. Stress tests may also be used to test the effect of exercise on people with shortness of breath and fatigue, borderline high blood pressure or irregular heartbeat.
Before the stress test, the patient is hooked up to a set of electrodes that allow for EKG readings throughout the exercise. A treadmill or other exercise machine is started at a slow speed and increases in speed every three minutes. This continues until the patient reaches his target heart rate, usually 85 percent of the maximum heart range for his age. The doctor then monitors the EKG pattern, heart rate, blood pressure, heart rhythm and symptoms of the patient during the test. If a patient experiences chest pain, shortness of breath or dizziness, the doctor may stop the test before the target heart rate is reached, according to Heartsite.com.