The effects of exercise during hemodialysis on physical performance and nutrition assessment.

OBJECTIVE: To assess the effects of participation in an intradialytic exercise program using commonly available measures of physical performance and parameters of nutrition assessment. SESIGN: Performance testing and nutrition assessment were completed on hemodialysis patients who participated in an in-center, intradialytic exercise program. Data were collected at initiation and after 3, 6, and 12 months of participation. One-tailed, paired t-test was used for statistical assessment.
SETTING: Free-standing, outpatient dialysis center with an average of 130 patients on staff-assisted hemodialysis. PATIENTS: Data were collected on 16 patients who completed 3 months in the program, 6 patients who completed 6 months in the program, and 4 patients who completed 12 months in the program. INTERVENTION: Patients participated in a progressive, self-paced exercise program including cycling before or during hemodialysis, or walking on a treadmill before hemodialysis. In addition to this, patients also had the option of doing stretching and/or light weight exercises during hemodialysis. MAIN OUTCOME MEASURES: Performance tests included 60-second sit-stand, 28-ft slow and brisk walk, 60-second stair climb, and 60-second leg lifts. Nutrition assessment included changes in estimated dry weight, hemoglobin, hematocrit, serum glucose, calcium, phosphorus, albumin, Kt/V, normalized protein catabolic rate (nPCR), average monthly interdialytic weight gain, and monthly mean predialysis and postdialysis blood pressure. Glycohemoglobin was assessed in diabetic patients. Patients' charts were reviewed for episodes of intradialytic cramping and hypotension.
RESULTS: All patients showed improvement in measures of physical performance at 3, 6, and 12 months. Mean phosphorus decreased from 1.94 +/- 0.45 mmol (6.02 +/- 1.4 mg/dL) by 11% at 3 months (P = 0.05) and by 26% at 12 months (P < 0.02). Patients who exercised for 12 months experienced a mean 16% reduction in blood glucose. Mean glucose levels for 7 diabetic patients decreased from 12.35 +/- 5.8 mmol/L (224.1 +/- 105) to 11. 66 +/- 1.9 mmol/L (211.7 +/- 34 mg/dL); however, this was not statistically significant. Mean glycohemoglobin levels for diabetic patients did not change significantly. Increases were seen in Kt/V, estimated dry weight, and serum albumin; however, these were not statistically significant. Decreases were noted in mean predialysis and postdialysis blood pressures and average interdialytic weight gains at 3, 6, and 12 months.
CONCLUSION: A formal intradialytic exercise regimen can produce objective evidence of improvement in physical performance and some measures of nutritional well-being over 3 to 12 months. Further research is needed to determine if these changes are a result of exercise alone or increased compliance with the medical and dietary regimen.