Physical activity patterns in chronic hemodialysis patients: Comparison of dialysis and nondialysis days
Objective
To determine physical activity patterns in chronic hemodialysis patients with a specific emphasis on the difference between dialysis and nondialysis days.
Minute-by-minute physical activity was assessed over a 7-day period using a triaxial accelerometer, which consists of raw numbers or counts calculated by the 3 axes of the accelerometer (PA counts). PA counts were extrapolated on a daily and hourly basis. Physical functioning tests included: sit-to-stand, 6-minute walk, and 1-repetition maximal leg press exercise. Laboratory values for serum concentrations of albumin, prealbumin, C-reactive protein, and cholesterol were also collected.
Main outcome measure
PA counts.
Results
Total PA counts were significantly lower on dialysis days when compared with nondialysis days (128,279 ± 74,009 versus 168,744 ± 95,168, respectively, P = .025). The average PA counts during the 4-hour dialysis time period were significantly lower on dialysis days when compared with nondialysis days (3,086 ± 3,749 versus 11,070 ± 7,695, respectively, P = .001). At postdialysis hours 1 and 2, PA counts on dialysis days were significantly higher than on nondialysis days (11,410 ± 5,340 versus 9,082 ± 6,646, P = .008, and 14,048 ± 9,728 versus 8,662 ± 6,433, P = .016, respectively). By postdialysis hour 4, PA counts on dialysis days had significantly decreased when compared with nondialysis days (6,068 ± 6,268 versus 10,512 ± 7,420 PA counts, P = .01, respectively). From postdialysis hours 5 to 20, there was no significant difference in PA counts between dialysis and nondialysis days.
Conclusion
This study shows that physical activity is lower on dialysis days when compared with nondialysis days, and this decrease is caused by the lack of activity during the 4-hour hemodialysis procedure. New behavior modification strategies involving physical activity, both during hemodialysis and on nondialysis days, must be examined in this patient population.
★Department of Medicine, Division of Nephrology, Vanderbilt University School of Medicine, Nashville, TN, USA
†Department of Medicine, Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, TN, USA
‡Department of Rehabilitation Services, Vanderbilt University School of Medicine, Nashville, TN, USA
Address reprint requests to T. Alp Ikizler, MD, Vanderbilt University Medical Center, 1161 21st Avenue South and Garland, Division of Nephrology, S-3223 MCN, Nashville, TN 37232-2372.
Supported in part by National Institutes of Health grants 2R01DK45604, 1K24DK62849, 5P30DK026657; National Institute of Diabetes, Digestive, and Kidney Disease grant 5P60DK020593; National Center for Research Resources grant 5M01RR-000095; and Food and Drug Administration Orphan Drug Grant Program Grant 000943, Norman S. Coplon Satellite Health Extramural Grant Program and National Kidney Foundation, Council on Renal Nutrition Grant (C.M.). Dr. Pupim is partly supported by the Marilyn Charitable Trust Young Investigator Grant of the National Kidney Foundation and the Vanderbilt University School of Medicine Clinician Scientist Award, as part of the Vanderbilt Physician Scientist Development Program. Dr. Chen is supported by National Institutes of Health grant DK02973 and Department of Defense DAMD 17-02-1-0716.
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