title: Effects of physical activity on cognitive functioning in middle age: evidence from the Whitehall II prospective cohort study.
abstract: OBJECTIVE
  We examined the association between physical activity and cognitive functioning in middle age.
  
  
  METHODS
  Data were derived from a prospective occupational cohort study of 10308 civil servants aged 35-55 years at baseline (phase 1; 1985-1988). Physical activity level, categorized as low, medium, or high, was assessed at phases 1, 3 (1991-1994), and 5 (1997-1999). Cognitive functioning was tested at phase 5, when respondents were 46-68 years old.
  
  
  RESULTS
  In both prospective (odds ratio [OR] = 1.65; 95% confidence interval [CI]=1.30, 2.10) and cross-sectional (OR=1.79; 95% CI=1.38, 2.32) analyses, low levels of physical activity were a risk factor for poor performance on a measure of fluid intelligence. Analyses aimed at assessing cumulative effects (summary of physical activity levels at the 3 time points) showed a graded linear relationship with fluid intelligence, with persistently low levels of physical activity being particularly harmful (OR=2.21; 95% CI=1.37, 3.57).
  
  
  CONCLUSIONS
  Low levels of physical activity are a risk factor for cognitive functioning in middle age, fluid intelligence in particular.
authors.affiliation: Department of Epidemiology and Public Health, University College London, England. archana.singh-manoux@st-maurice.inserm.fr
authors.forename: Archana
authors.initials: A
authors.lastname: Singh-Manoux
authors.forename: Melvyn
authors.initials: M
authors.lastname: Hillsdon
authors.forename: Eric
authors.initials: E
authors.lastname: Brunner
authors.forename: Michael
authors.initials: M
authors.lastname: Marmot
mesh_terms: D000328:Adult; D003071:Cognition / Q000502:physiology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008131:London; D008297:Male; D008875:Middle Aged