title: The association between frequency of physical activity and mortality risk across the adult age span.
abstract: OBJECTIVE
  To determine if the association between frequency of leisure-time physical activity and mortality risk differs across adulthood.
  
  
  METHODS
  9,249 adults from the NHANES III (1988-1994) were categorized as middle-aged (40-64 years), old (65-79 years) or very old (≥80 years), and as inactive (0 bouts of physical activity/week), lightly active (1-2 bouts/week), moderately active (3-4 bouts/week) or very active (5+ bouts/week).
  
  
  RESULTS
  In all age categories, lightly, moderately, and very active adults had a lower mortality risk compared to inactive adults (p < .001). In very old adults only, being very active was associated with a lower mortality risk compared to being lightly active (HR 0.80, 95% CI 0.64-0.98; p = .03) and moderately active (HR 0.80, 95% CI 0.65-0.98; (p = .03).
  
  
  CONCLUSIONS
  The association between physical activity frequency and mortality risk is strongest in very old adults. All adults and particularly very old adults may benefit from participating in physical activity five or more times a week.
authors.affiliation: School of Kinesiology and Health Science, York University, Toronto, ON, Canada.
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Brown
authors.forename: Michael C
authors.initials: MC
authors.lastname: Riddell
authors.forename: Alison K
authors.initials: AK
authors.lastname: Macpherson
authors.forename: Karissa L
authors.initials: KL
authors.lastname: Canning
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Kuk
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D005260:Female; D006801:Humans; D007899:Leisure Activities; D008297:Male; D008875:Middle Aged; D009026:Mortality / Q000639:trends*; D009043:Motor Activity / Q000502:physiology*; D009749:Nutrition Surveys; D018570:Risk Assessment; D013997:Time Factors; D014481:United States / Q000453:epidemiology
keywords: 80 and over; age groups; aged; leisure activities; survival