An exercise ECG records the electrical activity of your heart whilst you exercise. This test is sometimes called an exercise stress test or exercise tolerance test.
Small electrodes are stuck on to your chest. Wires from the electrodes are connected to the ECG machine. You will then be asked to exercise on a treadmill or on an exercise bike. The exercise starts at a very easy pace, and is gradually made more strenuous by increasing the speed and incline of the treadmill, or by putting some resistance on the bike wheel.