title: Atrial fibrillation and physical activity: Should we exercise caution?
abstract: OBJECTIVE
  To review the evidence on the effects of various levels of physical activity (PA) on the incidence of atrial fibrillation (AF) in both the general population and in endurance athletes.
  
  
  METHODS
  A PubMed search was done initially using the MeSH headings or text words (with the search-field descriptor TIAB [title and abstract]) atrial fibrillation and exercise or physical activity or athlet* or sport*, without additional filters. Conclusions regarding quality and strength of evidence were based on the GRADE (grading of recommendations, assessment, development, and evaluation) system.
  
  
  METHODS
  No interventional studies were available. Observational studies were therefore considered acceptable, and, although larger long-term prospective cohort studies were preferred, case-control or cross-sectional trials were also included in this review.
  
  
  RESULTS
  Available evidence suggests a dose-response association linking increased exercise levels with reduced incident AF in women. The same is true in men at low and moderate levels of exertional activity. In men only, high levels of PA are associated with increased risk of AF in most, but not all, studies. This risk is moderate, with a hazard ratio of 1.29 in one of the better studies. The risk of AF for most people who exercise regularly is lower than that of a matched sedentary population.
  
  
  CONCLUSIONS
  Atrial fibrillation is probably less common as PA increases, with a demonstrable dose-response relationship. Exercise at any level should be promoted for its effect on physical well-being and mortality reduction. In men exercising at high levels, beneficial effects on AF might be lost and risk might exceed that of the sedentary population; however, the evidence is neither robust nor consistent. These men should be made aware of this modest increase in risk should they choose to continue to engage in high levels of PA.
authors.affiliation: Dr Bosomworth is Honorary Lecturer in the Department of Family Practice at the University of British Columbia in Vancouver. jbosomworth@gmail.com.
authors.forename: N John
authors.initials: NJ
authors.lastname: Bosomworth
mesh_terms: D000328:Adult; D000368:Aged; D056352:Athletes; D001281:Atrial Fibrillation / Q000209:etiology*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D015444:Exercise; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013177:Sports / Q000502:physiology