The Pulmonary Function Testing Laboratories at Kirklin Clinic and UAB University Hospital are capable of doing cardiopulmonary exercise tests with expired gas analysis. These tests can be done on either a treadmill (typically with Bruce or modified Bruce protocol) or on a stationary bicycle. During the test, total exhaled ventilation, oxygen consumption, and carbon dioxide production are monitored continually along with the 12 lead electrocardiogram and arterial oxygen saturation via pulse oximetry. These tests are useful to evaluate the cause of shortness of breath and to determine overall exercise tolerance. Referral for the test must come from a UAB physician.