title: Mechanisms Involved in Exercise-Induced Cardioprotection: A Systematic Review.
abstract: BACKGROUND
  Acute myocardial infarction is the leading cause of morbidity and mortality worldwide. Furthermore, research has shown that exercise, in addition to reducing cardiovascular risk factors, can also protect the heart against injury due to ischemia and reperfusion through a direct effect on the myocardium. However, the specific mechanism involved in exerciseinduced cardiac preconditioning is still under debate.
  
  
  OBJECTIVE
  To perform a systematic review of the studies that have addressed the mechanisms by which aerobic exercise promotes direct cardioprotection against ischemia and reperfusion injury.
  
  
  METHODS
  A search was conducted using MEDLINE, Literatura Latino-Americana e do Caribe de Informação em Ciências da Saúde, and Scientific Electronic Library Online databases. Data were extracted in a standardized manner by two independent researchers, who were responsible for assessing the methodological quality of the studies.
  
  
  RESULTS
  The search retrieved 78 studies; after evaluating the abstracts, 30 studies were excluded. The manuscripts of the remaining 48 studies were completely read and, of these, 20 were excluded. Finally, 28 studies were included in this systematic review.
  
  
  CONCLUSIONS
  On the basis of the selected studies, the following are potentially involved in the cardioprotective response to exercise: increased heat shock protein production, nitric oxide pathway involvement, increased cardiac antioxidant capacity, improvement in ATP-dependent potassium channel function, and opioid system activation. Despite all the previous investigations, further research is still necessary to obtain more consistent conclusions.
authors.affiliation: Laboratório de Investigação Cardiovascular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Juliana Pereira
authors.initials: JP
authors.lastname: Borges
authors.affiliation: Laboratório de Investigação Cardiovascular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
authors.forename: Marcos Adriano
authors.initials: MA
authors.lastname: Lessa
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy / Q000379:methods*; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D054086:KATP Channels / Q000378:metabolism; D009203:Myocardial Infarction / Q000378:metabolism* / Q000503:physiopathology / Q000517:prevention & control; D015428:Myocardial Reperfusion Injury / Q000378:metabolism* / Q000503:physiopathology / Q000517:prevention & control; D013997:Time Factors
chemical_list: D000975:Antioxidants; D006360:Heat-Shock Proteins; D054086:KATP Channels
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