(HealthDay News) -- A stress test evaluates the way your heart works during exercise and while you're at rest.

The U.S. National Heart, Lung, and Blood Institute says your doctor may have ordered a stress test:

• To diagnose -- or determine the extent of -- coronary heart disease.
• To diagnose a problem with the heart's valves.
• To show how the heart withstands exercise after a heart attack.
• To determine how well a clog-clearing procedure called angioplasty has alleviated reduced blood flow to the heart.
• To determine if you have arrhythmia, an irregular heartbeat.
• To help explain why you can't catch your breath during exercise.