[Exercise tolerance in patients with chronic obstructive pulmonary disease in various stages of advanced disease].

The aim of the study was to investigate exercise tolerance in COPD patients. Eighty one subjects, 66 M and 15 F mean age 60.4 +/- 9.2 yrs, mean VC 2.56 +/- 0.81 L, FEV1 1.00 +/- 0.47 L., PaO2 58.4 +/- 10.1 Torr, PaCO2 45.1 +/- 8.9 Torr were studied. A symptom limited incremental exercise test on cycloergometer using ramp protocol was performed. Ventilatory parameters (breath by breath method), together with transcutaneous oxygen saturation and heart rate (continuously) were recorded. Four patients tolerated only unloaded pedalling (0 Watt), others workload from 5 to 80 Watts, with one exception of 120 Watts and two of 100 Watts. A significant correlation was found between VO2max and FEV1 (r = 0.67) and between StcO2 during exercise and StcO2 at rest (r = 0.31) and PaO2 at rest (r = 0.45). No correlation was found between VO2max and blood gases at rest and exercise. Exercise tolerance in COPD patients could be predicted from airway limitation. Patients with severe COPD presented with a disturbed anaerobic metabolism during exercise and in 18 of them anaerobic metabolism was present already at rest. A significant correlation was found between blood gas values at rest and StcO2 during exercise.