title: Relation of physical activity and cardiovascular fitness to coronary heart disease, Part I: A meta-analysis of the independent relation of physical activity and coronary heart disease.
abstract: BACKGROUND
  This paper is the first of two reports that together review the scientific evidence regarding the inverse relation between physical activity and cardiovascular fitness and coronary heart disease (CHD).
  
  
  METHODS
  In Part I, the evidence suggesting a causal link between physical activity and CHD protection independent of other CHD risk factors is reviewed, accounting for bias, confounding, and different study designs.
  
  
  RESULTS
  A strong, consistent inverse relation is found. Using meta-analytic techniques, the relative risk of the independent relation of physical inactivity to CHD is 1.37, with a 95 percent confidence interval (1.27-1.48).
  
  
  CONCLUSIONS
  A graded biologic response of CHD protection to physical activity is shown, but the intensity, duration, and frequency of activity necessary for CHD benefit remain unclear. Plausible biologic mechanisms for the inverse relation of physical activity to CHD are the risk factor modifications that accrue with physical activity.
authors.affiliation: Department of Family Medicine, Brown University/Memorial Hospital of Rhode Island, Pawtucket 02860.
authors.forename: C B
authors.initials: CB
authors.lastname: Eaton
mesh_terms: D015984:Causality; D003327:Coronary Disease / Q000453:epidemiology / Q000209:etiology; D015444:Exercise; D006801:Humans; D015201:Meta-Analysis as Topic; D010809:Physical Fitness; D012307:Risk Factors