title: Running and the development of disability with age.
abstract: OBJECTIVE
  To determine, by longitudinal study, whether regular vigorous running activity is associated with accelerated, unchanged, or postponed development of disability with increasing age.
  
  
  METHODS
  8-year prospective, longitudinal study with yearly assessments.
  
  
  METHODS
  451 members of a runners' club and 330 community controls who were initially 50 to 72 years old (also characterized as "ever-runners" [n = 534] and "never-runners" [n = 247], respectively).
  
  
  METHODS
  The dependent variable was disability as assessed by the Health Assessment Questionnaire and separately validated in these participant cohorts. Covariates included age, sex, body mass index, comorbid conditions, education level, smoking history, alcohol intake, mean blood pressure, initial disability level, family history of arthritis, and radiologic evidence of osteoarthritis of the knee in a subsample.
  
  
  RESULTS
  Initially, the runners were leaner, reported joint symptoms less frequently, took fewer medications, had fewer medical problems, and had fewer instances of and less severe disability, suggesting either that the average previous 12 years of running had improved health or that self-selection bias was present. After 8 years of longitudinal study, the differences in initial disability levels (0.026 compared with 0.079; P < 0.001) had steadily increased to 0.071 for runners compared with 0.242 for controls (P < 0.001). The difference was consistent for men and women. The rate of development of disability was several times lower in the runners' club members than in community controls; this difference persisted after adjusting for age, sex, body mass, baseline disability, smoking history, history of arthritis, or other comorbid conditions (slopes of progression of disability for the years 1984 to 1992, after adjusting for covariates: men in the runners' club, 0.004 [SE, 0.002]; community controls, 0.012 [SE, 0.002]; women in the runners' club, 0.009 [SE, 0.005]; community controls, 0.027 [SE, 0.004]; P < 0.002 for both sets of comparisons). In addition to differences in disability, there were significant differences in mortality between the runners' club members (1.49%) and community controls (7.09%) (P < 0.001). These differences remained significant after adjusting for age, sex, body mass, comorbid conditions, education level, smoking history, alcohol intake, and mean blood pressure (P < 0.002, conditional risk ratio for community controls compared with the runners, 4.27; 95% CI, 1.78 to 10.26).
  
  
  CONCLUSIONS
  Older persons who engage in vigorous running and other aerobic activities have lower mortality and slower development of disability than do members of the general population. This association is probably related to increased aerobic activity, strength, fitness, and increased organ reserve rather than to an effect of postponed osteoarthritis development.
authors.affiliation: Stanford University School of Medicine, California.
authors.forename: J F
authors.initials: JF
authors.lastname: Fries
authors.forename: G
authors.initials: G
authors.lastname: Singh
authors.forename: D
authors.initials: D
authors.lastname: Morfeld
authors.forename: H B
authors.initials: HB
authors.lastname: Hubert
authors.forename: N E
authors.initials: NE
authors.lastname: Lane
authors.forename: B W
authors.initials: BW
authors.lastname: Brown
mesh_terms: D000375:Aging / Q000502:physiology*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010809:Physical Fitness; D011446:Prospective Studies; D012307:Risk Factors; D012420:Running / Q000502:physiology*; D012727:Sex Characteristics; D016019:Survival Analysis