Exercise capacity in sarcoidosis. Study of 29 patients

Sarcoidosis is a systemic granulomatous disease of unknown etiology. Aims of this prospective study are to evaluate degree of impairment in pulmonary function tests (PFT), arterial blood gas analysis (ABG), respiratory muscle strength, exercise capacity and correlation of these parameters with radiological stages; to further evaluate the use of cardiopulmonary exercise testing in assessment of extent of pulmonary disease; and to discuss the pathophysiologic mechanisms of limitation in exercise capacity in patients with sarcoidosis.

29 patients with sarcoidosis were grouped according to their radiological stages (stage I: group 1; stage II, group 2; stage III, group 3). Groups 1, 2 and 3 included 11, 13 and 5 patients, respectively. PFT, cardiopulmonary exercise testing and ABG were performed for each patient.

Evaluation of all patients showed a significant decrement in exercise capacity. Patients in stage III had decreased diffusing capacity and exercise capacity. There was limitation in exercise capacity in stage I patients who had completely normal spirometry and diffusing capacity. We also found a correlation between radiological stages of the disease and exercise capacity, diffusing capacity and ABG.

Exercise capacity is impaired also in early stages of sarcoidosis and it was found to be the earliest impaired physiological parameter in sarcoid patients. Exercise intolerance, having mutifactorial basis, is correlated with radiological stages. Circulatory impairment and impaired heart rate response to exercise have effects on limitation in exercise capacity. Especially in advanced radiological stages of disease, ventilatory and gas exchange impairment also seems to be effective on limiting exercise in patients with sarcoidosis.