title: The Acute Risks of Exercise in Apparently Healthy Adults and Relevance for Prevention of Cardiovascular Events.
abstract: BACKGROUND
  Increased physical activity (PA) is associated with improved quality of life and reductions in cardiovascular (CV) morbidity and all-cause mortality in the general population in a dose-response manner. However, PA acutely increases the risk of adverse CV event or sudden cardiac death (SCD) above levels expected at rest. We review the likelihood of adverse CV events related to exercise in apparently healthy adults and strategies for prevention, and contextualize our understanding of the long-term risk reduction conferred from PA.
  
  
  METHODS
  A systematic review of the literature was performed using electronic databases; additional hand-picked relevant articles from reference lists and additional sources were included after the search.
  
  
  RESULTS
  The incidence of adverse CV events in adults is extremely low during and immediately after PA of varying types and intensities and is significantly lower in those with long-standing PA experience. The risk of SCD and nonfatal events during and immediately after PA remains extremely low (well below 0.01 per 10,000 participant hours); increasing age and PA intensity are associated with greater risk. In most cases of exercise-related SCD, occult CV disease is present and SCD is typically the first clinical event.
  
  
  CONCLUSIONS
  Exercise acutely increases the risk of adverse CV events, with greater risk associated with vigorous intensity. The risks of an adverse CV event during and immediately after exercise are outweighed by the health benefits of vigorous exercise performed regularly. A key challenge remains the identification of occult structural heart disease and inheritable conditions that increase the chances of lethal arrhythmias during exercise.
authors.affiliation: Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada; UHN/Mt Sinai Division of Cardiology, Heart and Stroke/Richard Lewar Centres of Excellence in Cardiovascular Research, Toronto, Ontario, Canada. Electronic address: jack.goodman@utoronto.ca.
authors.forename: Jack M
authors.initials: JM
authors.lastname: Goodman
authors.affiliation: Department of Human Health and Nutritional Sciences, College of Biological Science, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Jamie F
authors.initials: JF
authors.lastname: Burr
authors.affiliation: Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Laura
authors.initials: L
authors.lastname: Banks
authors.affiliation: Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Scott G
authors.initials: SG
authors.lastname: Thomas
mesh_terms: D000328:Adult; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000517:prevention & control*; D015444:Exercise / Q000502:physiology*; D014943:Global Health; D006801:Humans; D015994:Incidence; D011788:Quality of Life; D012016:Reference Values; D012307:Risk Factors