A treadmill test or stress EKG is an EKG that is recorded during exercise. The patient walks on a treadmill while an EKG machine records the electrical activity of the heart. The test may uncover problems with heart rhythm or blood supply to the heart which cannot be found on an EKG taken at rest. It can also be used to decide how much exercise is safe for you. This is valuable for planning a cardiac rehabilitation program after a heart attack or heart surgery. A technician will attach electrodes to the skin on your chest. Your blood pressure will be taken and a resting EKG will be recorded. You will begin walking at a low level which gradually increases, as both the speed and slope of the treadmill are increased. The test will continue until you have reached a certain pulse rate, certain EKG changes occur, or you are too tired to continue.