EXERCISE AND RESTING PULMONARY-FUNCTION IN SARCOIDOSIS

Patients with sarcoidosis frequently complain of exercise intolerance but reports of the value of static tests of pulmonary function in pred icting disability have been contradictory. We studied 32 patients with sarcoidosis and dyspnea, correlating x-ray stages, spirometry and lun g volume measurements with graded exercise testing. Patients demonstra ted a reduction in maximum workload (Wmax) when compared to an age mat ched group of 7 normal subjects (p<0.05). While ventilation (VEmax) at Wmax was lower in patients, when adjusted for workload (V/E/watt) the re was relative hyperventilation (p<0.05). Exercise induced arterial d esaturation (PaO2 decrease) was significantly related to resting DLCO% predicted (r=0.74, p<0.05). When patients were separated into subgrou ps of> < DLCO 55% predicted, the lower diffusing capacity group had a lower Wmax and greater fall in exercise PaO2. Chest radiograph staging and the vital capacity proved to be poor predictors of exercise capac ity though maximum impairment was associated with advanced x-ray chang es and greater decreases in vital capacity. In conclusion, the magnitu de of functional impairment may vary widely from apparent histopatholo gic involvement as reflected by chest x-ray and lung volumes. Actual e xercise testing is necessary to accurately characterize and quantitate the impairment in patients with sarcoidosis complaining of dyspnea.