Cardiopulmonary exercise testing.

Cardiopulmonary exercise testing is an objective method of assessing the functional capacity of a patient. In contrast to clinical assessment and resting investigations, exercise testing is useful in detecting early changes in patients with cardiac or respiratory disease. Although a number of different types of ergometers can be used for testing, the ones used commonly are the cycle and treadmill. Comparison of these two modes of exercise shows no significant clinical difference between them; therefore, either can be used for routine cardiopulmonary exercise testing. There are various types of exercise protocols, but generally the protocol should involve large muscle groups and should be tolerated by the population being tested. The main goal when selecting an exercise protocol is to strike a balance between workload increments that do not prematurely fatigue the subject and at the same time allow the subject to reach a maximum power output within 8 to 15 minutes. Whatever the exercise test protocol used, the intensity should be increased to a symptom-limited maximum. This procedure is safe as long as contraindications for starting a test and indications for terminating a test are adhered to strictly. The assessment of cardiorespiratory responses during exercise ranges from simple and noninvasive techniques to those that are invasive and complex. In the majority of cases all the information needed for proper assessment of the patient can be acquired with simple noninvasive techniques.