A stress test, also called a treadmill test or an exercise ECG, is used to record the heart’s electrical activity during exercise. This test can be effective because some heart problems only show up when the heart is working hard.

To perform the test, an ECG is conducted before, during, and after a patient exercises on a treadmill. In some cases, the patient’s breathing rate and blood pressure may also be measured.

As with a standard ECG, a stress test is used to evaluate abnormal heartbeats, areas of damage, inadequate blood flow, and heart enlargement. The test can show if the blood supply is reduced in the arteries that supply the heart. It also helps providers determine the kind and level of exercise appropriate for a patient.

It’s important to note that exercise tests, although useful, are not always completely reliable. Unfortunately, the test may show a problem where none exists, or not show a problem when one does exist.