This test provides information about how your heart works during physical stress. Some heart problems are easier to diagnose when your heart is working hard and beating fast. During stress test, you exercise (walk or run or pedal a stationary bike) to make your heart work hard and beat fast. Tests are done on your heart while you exercise.It helps to detect abnormal changes in your heart rate or blood pressure, any symptoms like shortness of breath, chest pain (especially if they occur at low levels of exercise), abnormal changes in your heart rhythm or electrical activity. If you can't exercise for as long as what is considered normal for someone your age, it may be a sign that not enough blood is flowing to your heart.