Exercise testing is a non-invasive procedure that provides diagnostic and prognostic information and evaluates an individual’s capacity for exercise. The treadmill test is basically continuous EKG monitoring during physical exertion, with close attention to the blood pressure, O2 saturation and heart rate. Its major use is to detect significant coronary artery disease (Blockages in the coronary arteries). Frequently the test is used to evaluate patients with chest pain, shortness of breath, fatigue, and arrhythmia’s (irregular heartbeats). It also provides assessment of the exercise capacity, circulation to the legs, O2 saturation, blood pressure and heart response to exercise. The test is performed according to standard protocols. The most commonly used is the Bruce protocol. It consists of three-minute stages with gradually increasing speed and slope. This allows physicians anywhere in the world to communicate and compare test results. One of the end-points of the exercise test is to achieve at least 85% of the age predicted maximum heart rate. If the patient has a significant narrowing of the coronary arteries, the exercise may elicit chest discomfort (angina pectoris) or changes in the EKG.