title: Self-reported walking speed: a useful marker of physical performance among community-dwelling older people?
abstract: BACKGROUND
  Walking speed is central to emerging consensus definitions of sarcopenia and frailty as well as being a major predictor of future health outcomes in its own right. However, measurement is not always feasible in clinical settings. We hypothesized that self-reported walking speed might be a good marker of objectively measured walking speed for use in this context.
  
  
  METHODS
  We investigated the relationship between self-reported and measured walking speed and their associations with clinical characteristics and mortality using data from 730 men and 999 women, aged 61 to 73 years, who participated in the Hertfordshire Cohort Study. Walking speed was measured over 3 meters. Participants rated their walking speed as "unable to walk," "very slow," "stroll at an easy pace," "normal speed," "fairly brisk," or "fast."
  
  
  RESULTS
  Self-reported walking speed was strongly associated with measured walking speed among men and women (P < .001). Average walking speeds ranged from 0.78 m/s (95% CI 0.73-0.83) among men with "very slow" self-reported walking speed to 0.98 m/s (95% CI 0.93-1.03) among "fast" walkers (corresponding figures for women were 0.72 m/s [95% CI 0.68-0.75] and 1.01 m/s [95% CI 0.98-1.05]). Self-reported and measured walking speeds were similarly associated with clinical characteristics and mortality; among men and women, slower self-reported and measured walking speeds were associated (P < .05) with increased likelihood of poor physical function, having more systems medicated and with increased mortality risk, with and without adjustment for sociodemographic and lifestyle factors (hazard ratios for mortality per slower band of self-reported walking speed, adjusted for sociodemographic and lifestyle characteristics: men 1.44 [95% CI 1.11-1.87]; women 1.35 [95% CI 1.02-1.81]).
  
  
  CONCLUSIONS
  Self-reported walking speed is a good marker of measured walking speed and could serve as a useful marker of physical performance in consensus definitions of sarcopenia and frailty when direct measurement of walking speed is not feasible.
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, UK. Electronic address: hes@mrc.soton.ac.uk.
authors.forename: Holly E
authors.initials: HE
authors.lastname: Syddall
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, UK.
authors.forename: Leo D
authors.initials: LD
authors.lastname: Westbury
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, UK.
authors.forename: Cyrus
authors.initials: C
authors.lastname: Cooper
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, UK; Faculty of Medicine, Academic Geriatric Medicine, University of Southampton, Southampton General Hospital, Southampton, UK.
authors.forename: Avan Aihie
authors.initials: AA
authors.lastname: Sayer
mesh_terms: D000054:Acceleration; D000368:Aged; D000375:Aging / Q000502:physiology; D015415:Biomarkers; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D015577:Geriatric Assessment / Q000379:methods*; D006304:Health Status; D006801:Humans; D057187:Independent Living; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010809:Physical Fitness / Q000502:physiology*; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D057566:Self Report; D016019:Survival Analysis; D016138:Walking / Q000502:physiology*
chemical_list: D015415:Biomarkers
keywords: Walking speed; gait speed; mortality; physical performance; sarcopenia; self-reported