What is an Exercise Stress Test?

An exercise stress test is a diagnostic tool used to observe a person’s heart activity during physical exertion. People who have a history of heart disease or are at risk of heart disease can benefit from the test, because it can detect serious medical problems. Athletes can use exercise stress tests to determine their current aerobic fitness level. The test monitors heart activity and blood pressure while a person walks on a treadmill at an increasingly faster rate.

Also known as a cardiac stress test or a treadmill test, an exercise stress test helps doctors determine how much physical activity a person’s heart can handle. The more active a body is, the more oxygen it needs. In turn, the heart begins to pump more blood so that the body can produce this needed oxygen. The exercise test will reveal whether the blood slows down in the heart’s arteries because of a medical issue.

A doctor might order an exercise stress test for a person who is at high risk for heart problems or who has a pre-existing heart problem. If a person has been experiencing shortness of breath or chest pains, the exercise test can be used to diagnose the cause of the symptoms. The test also can be used to check on the success of a heart-related procedure. In addition, the test can be used to predict the likelihood of a future heart attack.

Although an exercise stress test is often used to diagnose heart problems, it also can be used to test an athlete’s stamina. When the stress test is performed on athletes, the Bruce protocol is often used. Developed by Dr. Robert A. Bruce, this is a diagnostic test that measures how much oxygen an athlete can consume and utilize while moving on a treadmill at increasing speeds. Coaches will sometimes order a Bruce protocol test on an athlete in order to monitor the athlete’s fitness level.

Preparation for an exercise stress test is essential for the most accurate results. A person should not smoke, drink or eat anything for at least three hours before the test. Regular medication, however, should be taken as usual that day unless the tending physician says otherwise.

Whether an exercise stress test is used for medical or athletic purposes, it always involves a treadmill. A person wears electrodes on his or her chest and a blood pressure cuff on one arm while walking on a treadmill. Medical professionals can then monitor the person's heart activity and blood pressure. The treadmill will begin slowly and then increase in speed until the person reaches a target heart rate or experiences adverse effects such as chest pain.

An abnormal exercise stress test result might indicate several different things. It could show heart function abnormalities, such as arrhythmia, during exercise. A medical problem as serious as coronary artery disease also might be detected by an exercise stress test. In some cases, an abnormal result simply means that the person is in poor aerobic shape and needs to exercise more.