ABSTRACT
BACKGROUND: Individuals with end-stage renal disease on hemodialysis therapy have reduced aerobic exercise capacity and reduced muscle strength. METHODS: This was a single-blind, randomized, placebo-controlled trial of an exercise intervention in hemodialysis patients administered erythropoietin. The intervention consisted of progressive resisted isotonic quadriceps and hamstrings exercise and training on a cycle ergometer three times weekly for 12 weeks. Individuals in the control group underwent a nonprogressive program of range-of-motion exercises. Both groups were observed for an additional 5 months without intervention. Outcomes were assessed without knowledge of treatment assignment at baseline, 12 weeks, and 5 months. A healthy age- and sex-matched sample provided comparative data. RESULTS: Our sample was relatively high functioning, with a mean score on the Physical Function subscale of the Short Form 36 (SF-36) of 76 of 100. At 12 weeks, there were large and statistically significant differences in favor of the experimental group on the submaximal exercise test (14 W; 95% confidence interval, 2 to 26) and muscle strength (45 lb; 95% confidence interval, 9 to 81), but not in the 6-minute walk, symptoms questionnaire, or SF-36. Differences between the intervention and control groups at 12 weeks were not evident on retesting 5 months after the end of the intervention. Compared with the healthy sample, patients were significantly lower functioning on the submaximal exercise test, muscle strength, and 6-minute walk test at baseline. CONCLUSION: In this high-functioning sample, the exercise program improved physical impairment measures, but had no effect on symptoms or health-related quality of life. The impact on patients with a greater degree of physical dysfunction needs to be rigorously studied.
