Exercise testing in radiologically-limited, simple pulmonary silicosis.

Forty-five consecutive patients (17 non-smokers and 28 smokers) affected by pulmonary silicosis with limited profusion of radiologic small opacities of "p" type underwent physical examination; resting standard pulmonary function tests (PFT); and progressive, multistage, treadmill-based exercise testing (ET). Results show that, in 78 percent of all patients, maximum oxygen uptake (VO2max) was below 80 percent of predicted, and in most cases this was accompanied by a reduction of anaerobic threshold and/or oxygen pulse. In our group, VO2max predicted was uncorrelated with PFT parameters, symptoms and x-ray picture. No significant differences in response to exercise were observed between smokers and non-smokers. Therefore, exercise was limited by factors other than ventilatory limitation. It is concluded that ET is not more sensitive than PFT for assessing ventilatory impairment in patients with early, simple silicosis, even though it may be valuable for providing information about other sources of exercise limitation.