Exercise Stress

An exercise treadmill stress test helps determine how well the heart responds to the increase in workload caused by exercise.

Exercise treadmill stress tests can help:

• Diagnose coronary artery disease (obstruction of the blood vessels that supply oxygen to the heart)
• Determine whether symptoms such as chest pain, shortness of breath or nausea are related to a heart problem
• Evaluate the risk of suffering a heart attack
• See if there has been an improvement in cardiac function after cardiac procedures
• Help determine a suitable exercise program
• Once on the treadmill, as the level of exercise gets more intense, the body requires more oxygen and the heart has to pump more blood. As the heart pumps more strongly, the heart muscle also needs more oxygen

If the heart muscle does not receive enough oxygen, symptoms such as chest pain and shortness of breath indicate that the coronary arteries may be partially blocked by plaque.

Some stress tests are done with additional imaging tests that generate images of the heart before and after exercise. Nuclear stress tests use a radioisotope that is absorbed by the heart muscle. The patient is then scanned and images of how well the heart takes up radioisotope before and after exercise can be obtained and compared. This provides more information about how the heart responds to effort in addition to the electrocardiogram (ECG) from the treadmill test alone.

For patients who cannot walk on a treadmill, other stress test options include:

• Substitute a stationary bike for a treadmill
• The injection of medicines that stimulate the heart and simulate the effects produced on the heart by exercise