Muscle dysfunction is a major problem for patients with end-stage renal disease (ESRD). Specifically, these patients experience approximately three-fold greater muscle fatigue of the lower extremities during intermittent submaximal contractions than healthy control subjects. Thus, a treatment that could ameliorate muscle fatigue in this population has the potential to increase endurance during activities of daily living and improve quality of life. Dialysis patients have been shown to have high levels of various markers of oxidative stress, and oxidative stress has been associated with excessive muscle fatigue in other patient populations, but this link has not been established in the ESRD population.
Comparisons: The amount of muscle fatigue during intermittent submaximal quadriceps exercise between dialysis patients and controls will be compared. In addition, the degree of exercise-induced increase in markers of oxidative stress in muscle and in plasma will be compared between dialysis patients and controls and between dialysis patients who have received N-acetylcysteine for 6 days and those who have received placebo capsules.
