Physical Working Capacity in Uremic Patients

Abstract

By the time patients have reached end-stage renal failure and need dialysis, a majority are experiencing debilitating fatigue and lack of energy. Few dialysis patients are gainfully employed and many are unable to care for themselves. The pervasive feeling of fatigue among uremic patients, in conjunction with the growing proportion of elderly and very old patients on dialysis, makes it necessary for nephrologists to focus their attention on which factors actually are responsible for rendering their patients dysfunctional in their everyday lives.

Predialysis patients have a reduced physical exercise capacity compared to the expected norm, with further deterioration as uremia progresses (7, Fig. 1). Subsequently, when these patients reach end-stage renal failure and need dialysis their exercise capacity is only 40-60% of the expected norm (26). The cause of this physical deterioration is multifactorial. Glomerular filtration rate (GFR) is one important determinant for maximal exercise capacity in the predialysis phase. The anemia of end-stage renal disease and skeletal muscle disorder are two major factors affecting physical exercise capacity in the uremic patient. Furthermore, progressive myocardial dysfunction, hyperparathyroidism and malnutrition with muscular wasting are all conditions with negative effects on physical exercise capacity and muscular function. In turn all these factors lead to a sedentary way of life which further contributes to the physical, psychological and social waning of these patients.