The influence of dialysis solution on the exercise capacity in patients on CAPD

The present study was conducted to see whether the exercise capacity can be altered by intraperitoneal dialysis solution in patients on CAPD. Symptom-limited progressive treadmill tests with respiratory gas analysis were performed in patients on long-term CAPD, and exercise time (ET), maximal oxygen uptake (VO2 max) and ventilatory anaeorbic threshold (AT) were obtained. The treadmill tests were carried out before and after the drainage of 2-liters of dialysis solution. The dialysate bag with the fluid had either been carried by patients on their backs (test A) or been kept apart from their bodies (test B) during exercise, i.e. an apparent body weight in test B without the CAPD bag decreased by 2 kg as compared with the control. VO2max, AT or ET in test A did not change, whereas ET in the test B was prolonged after the drainage of dialysis solution (before: 437 +/- 170 sec, after: 479 +/- 158 sec, n = 10, p less than .01). No change was noted in VO2max or AT in test B. We conclude that the dialysis solution retained in the peritoneal cavity affects ET by acting as an extra-weight, although the solution has no influence on VO2max and AT.