Exercise Stress Test is a diagnostic test in which a person walks on a treadmill or pedals a stationary bicycle while hooked up to equipment that monitors the heart. The test monitors heart rate, breathing, blood pressure, electrical activity (on an electrocardiogram) and the person’s level of tiredness. It shows if the heart’s blood supply is sufficient and if the heart rhythm is normal. (Also known as Treadmill Test, Exercise Test, Exercise Cardiac Stress Test or ECST.)