title: Reference values for a multiple repetition 6-minute walk test in healthy adults older than 20 years.
abstract: OBJECTIVE
  To (1) identify greatest 6-minute walk distance (6MWD) from among several repetitions (best 6MWD) in a wide age range of healthy volunteers to develop reference values for the multiple repetition 6MWD, and (2) investigate the influence of demographics, anthropometrics, and habitual exercise activity on best 6MWD.
  
  
  METHODS
  Four 6MWD were performed on the same day in a 20-meter corridor by 41 male and 38 female healthy volunteers ranging in age from 20 to 80 years. The greatest 6MWD by each subject from among four 6MWDs was the primary outcome measure.
  
  
  RESULTS
  Eighty-six percent had their best 6MWD after the first walk; an average increase of 43 meters was observed from first to best 6MWD (P < 0.003). Best 6MWD averaged 698 +/- 96 meters and was inversely related to age (P < 0.001), directly to height (P < 0.001), and was greater in men than women (P < 0.0002). A regression model accounted for 41% of between-subject variability in best 6MWD (P < 0.00000001). In a subset of older subjects, predicted 6MWD significantly underestimated measured best 6MWD when reference values were used from another study where test familiarization was not provided, but this difference disappeared when value were used from the present and a third study where test familiarization was provided.
  
  
  CONCLUSIONS
  The present study is the first to provide predicted 6MWD values performed with multiple repetitions and for subjects in the 20-40-year-old age range. Selection of appropriate predicted 6MWD values for interpretation of performance should be guided by subject age and degree of test familiarization provided.
authors: Respiratory Division, Department of Medicine, Montreal Chest Institute, Royal Victoria Hospital, Montreal, Quebec, Canada.
authors: W J
authors: WJ
authors: Gibbons
authors: N
authors: N
authors: Fruchter
authors: S
authors: S
authors: Sloan
authors: R D
authors: RD
authors: Levy
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D005080:Exercise Test / Q000592:standards*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D016138:Walking / Q000502:physiology*