A standard exercise stress test uses an EKG (electrocardiogram) to detect and record the heart’s electrical activity.

An EKG shows how fast your heart is beating and the heart’s rhythm (steady or irregular). It also records the strength and timing of electrical signals as they pass through your heart.

During a standard stress test, your blood pressure will be checked. You also may be asked to breathe into a special tube during the test. This allows your doctor to see how well you’re breathing and measure the gases that you breathe out.

A standard stress test shows changes in your heart’s electrical activity. It also can show whether your heart is getting enough blood during exercise.

Source: National Heart, Lung, and Blood Institute; National Institutes of Health; U.S. Department of Health and Human Services.