IMPAIRMENT OF EXERCISE CAPACITY IN VARIOUS GROUPS OF HIV-INFECTED PATIENTS

It is known that pulmonary function is impaired during the course of H IV infection even in early stages. In order to estimate the resulting reduction of exercise capacity, different groups of HIV patients were investigated. Group 1 consisted of 20 patients without a history of re spiratory disease and without actual lung disease, group 2 of 18 patie nts with a former episode of Pneumo-cystis carinii pneumonia (PCP) wit hout actual lung disease, and group III of 37 patients with different broncho-pulmonary complications including PCP. 20 normal subjects serv ed as controls. Spirometry, diffusing capacity (DL(co)) and exercise t ests including arterial blood gas analysis (BGA) were performed in pat ients and controls. Compared to the controls group 1 patients revealed a decreased DL(co) (TCO: 83 +/- 15 vs. 67 +/- 15%(pred.norm.)) while spirometric data were normal. VO2 and O-2 pulse at the anaerobic thres hold (17.7 +/- 5.1 vs. 14.3 +/- 2.6 ml/kg min and 10.8 +/- 4.0 vs. 8.6 +/- 1.9 ml/beat, respectively) and maximum exercise (33.9 +/- 9.7 vs. 22.1 +/- 3.4 ml/kg min and 15.0 +/- 5.0 vs. 11.3 +/- 2.5, respectivel y) were decreased, whereas AaDO(2), V-D/V-T, and the HR/VO2 slope were normal. The reserves of heart rate and ventilation were high. Except for a reduced maximum work rate in group 1, no significant difference was found between groups 1 and 2. Group 3 patients differed most from groups 1 and 2 with respect to spirometry, DL(co) and AaDO(2), rather than VO2. VO2max and maximum work rate correlated with the Waiter Reed classification: r = 0.72 (p less than or equal to 0.0001) and r = 0.7 8 (p less than or equal to 0.0001), respectively, suggesting that a mo re advanced stage of immunodeficiency leads to a decreased exercise ca pacity. There was also a significant correlation between maximum work rate and the Broca index: r = 0.57 (p less than or equal to 0.0001). W e conclude that an impairment of DL(co) and exercise capacity is assoc iated with the infection of HIV-1. Analysis of gas exchange patterns s uggests that the cause of exercise limitation in groups 1 and 2 is due to anemia and a neuromuscular disorder in the exercising muscles, rat her than pulmonary limitations, as were observed in group 3.