Factors Limiting Physical Working Capacity in Predialytic Uraemic Patients

ABSTRACT The exercise capacity of 20 predialytic uraemic patients (mean age 43±12 years) was studied prospectively. Nine of these patients were examined twice in a longitudinal study. The maximal working capacity, measured by standardized exercise test on a bicycle ergometer, averaged 74±19% of the expected normal. Normal exercise ECG were registered in 16 out of 20 patients. Total hemoglobinkg body weight (THb) was 67±16% of the expected normal and serum parathyroid hormone concentration (PTH) was 39±39 μg/l (normal range 0.5-1.5). Partial correlation showed a correlation between exercise capacity and PTH (p<0.05). In the longitudinal study the decrease in steady state exercise capacity was correlated to the decrease in THb (p<0.05), but not to the increase in PTH. In conclusion, patients with predialytic uraemia have a reduced maximal working capacity, due to several possible factors one of which is a reduced THb. Ischaemic heart disease seems to be of minor importance.