title: Association of physical activity and atrial fibrillation.
abstract: BACKGROUND
  There is controversy regarding the association of physical activity (PA) and atrial fibrillation (AF). This systematic review aims to summarize the evidence regarding the association of PA at different levels and AF.
  
  
  METHODS
  A structured search of databases was performed until December 2009. Studies that investigated the association between PA and AF were included and assessed by 2 researchers according to selection criteria and methodological quality. The overall quality of evidence was rated according to the Grade system.
  
  
  RESULTS
  Of 855 publications, 10 met the inclusion criteria. The risk of uncontrolled bias and confounding was profound and there was substantial heterogeneity regarding observed associations. One methodologically rigorous study reported substantial risk reductions associated with moderate intensity PA. Another indicated modest increases in risk with high levels of vigorous PA. Five methodologically less reliable studies reported large increases in risk due to regular sport practice.
  
  
  CONCLUSIONS
  The overall quality of evidence indicating increases in risk of AF is low. Most reports of large increases in risk appear to be overestimated substantially. In light of the public health importance of regular PA, contradictory recommendations concerning the participation in PA should be considered cautiously before more rigorous studies have investigated this issue.
authors.affiliation: Institute for Social Medicine, Epidemiology, and Health Economics, Charite University Medical Centre, Berlin, Germany.
authors.forename: Falk
authors.initials: F
authors.lastname: Müller-Riemenschneider
authors.forename: Frank
authors.initials: F
authors.lastname: Andersohn
authors.forename: Sabine
authors.initials: S
authors.lastname: Ernst
authors.forename: Stefan N
authors.initials: SN
authors.lastname: Willich
mesh_terms: D001281:Atrial Fibrillation / Q000209:etiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D018570:Risk Assessment; D013177:Sports