[Ergometrically determined work capacity in chronic hemodialysis treatment]

To evaluate the degree of physical activity in hemodialysis patients, working capacity was assessed by bicycle ergometry in 16 hemodialysis patients (mean age 47 +/- 12 [SD] years). The mean length of dialysis treatment was 21 +/- 17 months. The laboratory and clinical findings were as follows (mean values +/- SD): urea 34 +/- 6 mmol/l; creatinine 1127 +/- 169 mumol/l; potassium 5.7 +/- 0.63 mmol/l; calcium 2.25 +/- 0.22 mmol/l; phosphate 1.76 +/- 0.54 mmol/l; hemoglobin 8.54 +/- 1.02 g/dl; hematocrit 26.1 +/- 2.9%; blood pressure 140 +/- 18/86 +/- 9 mm Hg; nerve conduction velocity 39.5 +/- 6.5 m/sec. Mean working capacity was 58 +/- 31 W (41 +/- 24% of normal values) and the specific working capacity (watts/kg body weight) was 0.79 +/- 0.54. The duration of exercise testing was 4.9 +/- 2 min. The ergometry had to be discontinued because of the following reasons: leg fatigue (10 patients); general fatigue (3); dyspnea (1); attainment of maximal heart rate (2). The maximal blood pressure during exercise testing was 149 +/- 21/86 +/- 14 mm Hg and the maximal increase in heart rate 117 +/- 34 beats/min. In patients treated with a beta-blocker agent for hypertension, maximal increase in blood pressure was comparable to normotensive patients. There was a negative correlation between working capacity and the age of the patients (r = 0.77; p less than 0.01). A positive correlation was found between working capacity and the serum creatinine level (r = 0.52; p less than 0.05).