Exercise testing in pulmonary sarcoidosis.

The variable natural history of sarcoidosis and the toxicity of corticosteroids result in many clinical situations where there is controversy concerning the need for treatment. Progressive incremental testing is an excellent method to identify physiologic mechanisms responsible for exercise limitation. It is therefore ideal to determine if subjective symptoms such as dyspnea are due to cardiac abnormalities, pulmonary abnormalities, or poor physical conditioning. Thirty-one patients with sarcoidosis underwent progressive incremental exercise testing. Four of 14 asymptomatic patients and eight of 17 symptomatic patients demonstrated pulmonary abnormalities which potentially limited exercise tolerance. These consisted of an abnormal respiratory pattern or gas exchange abnormalities, or both. Patients with completely normal routine pulmonary function studies almost always performed normally with exercise. Symptomatic patients with multiple abnormalities on routine pulmonary function studies invariably demonstrated a pulmonary limitation on exercise testing. Patients with one or two abnormalities on routine pulmonary function studies, regardless of the presence or absence of parenchymal infiltrates, required exercise testing to determine if symptoms were due to physiologically significant abnormalities of the respiratory system. The important variables necessary to be measured, arterial desaturation and an abnormal respiratory pattern, can be measured noninvasively with a minimum of equipment.