title: Physical activity levels in patients on hemodialysis and healthy sedentary controls.
abstract: BACKGROUND
  Patients on dialysis have reduced exercise tolerance compared with age-matched sedentary controls. The reasons for this debility have not been fully elucidated, but physical inactivity could be a contributing factor. The purpose of the current study was to determine whether patients on hemodialysis are less active than healthy sedentary controls and to explore clinical correlates of physical activity level in a group of hemodialysis patients.
  
  
  METHODS
  Thirty-four hemodialysis patients and 80 healthy sedentary individuals participated in the study. Physical activity was measured for seven days with a three-dimensional accelerometer and with an activity questionnaire.
  
  
  RESULTS
  Vector magnitude values from the accelerometer for the dialysis and control subjects were 104,718 +/- 9631 and 161,255 +/- 6792 arbitrary units per day, respectively (P < 0.0001, mean +/- SEM). The estimated energy expenditure values derived from the questionnaire were 33.6 +/- 0.5 kcal/kg/day and 36.2 +/- 0.5 kcal/kg/day (P = 0.002). The difference between patients on dialysis and controls increased with advancing age. Among the dialysis subjects, some measures of nutritional status correlated with physical activity level, including serum albumin concentration (r = 0.58, P = 0.003), serum creatinine concentration (r = 0.37, P = 0. 03), and phase angle derived from bioelectrical impedance analysis (r = 0.40, P = 0.02).
  
  
  CONCLUSIONS
  Patients on hemodialysis are less active than healthy sedentary controls, and this difference is more pronounced among older individuals. There is an association between the level of physical activity and nutritional status among patients on dialysis. These findings are of great concern, given the trend toward increasing age in incident dialysis patients and the well-known association between inactivity and increased mortality in the general population.
authors.affiliation: Divisions of Nephrology, San Francisco VA Medical Center, San Francisco, California 94121, USA. johanse@itsa.ucsf.edu
authors.forename: K L
authors.initials: KL
authors.lastname: Johansen
authors.forename: G M
authors.initials: GM
authors.lastname: Chertow
authors.forename: A V
authors.initials: AV
authors.lastname: Ng
authors.forename: K
authors.initials: K
authors.lastname: Mulligan
authors.forename: S
authors.initials: S
authors.lastname: Carey
authors.forename: P Y
authors.initials: PY
authors.lastname: Schoenfeld
authors.forename: J A
authors.initials: JA
authors.lastname: Kent-Braun
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D003404:Creatinine / Q000097:blood; D017097:Electric Impedance; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008722:Methods; D008875:Middle Aged; D009043:Motor Activity; D009752:Nutritional Status; D012016:Reference Values; D006435:Renal Dialysis; D012709:Serum Albumin / Q000032:analysis; D011795:Surveys and Questionnaires
chemical_list: D012709:Serum Albumin; D003404:Creatinine