title: Reduction in Post-Marathon Peak Oxygen Consumption: Sign of Cardiac Fatigue in Amateur Runners?
abstract: BACKGROUND
  Prolonged aerobic exercise, such as running a marathon, produces supraphysiological stress that can affect the athlete's homeostasis. Some degree of transient myocardial dysfunction ("cardiac fatigue") can be observed for several days after the race.
  
  
  OBJECTIVE
  To verify if there are changes in the cardiopulmonary capacity, and cardiac inotropy and lusitropy in amateur marathoners after running a marathon.
  
  
  METHODS
  The sample comprised 6 male amateur runners. All of them underwent cardiopulmonary exercise testing (CPET) one week before the São Paulo Marathon, and 3 to 4 days after that race. They underwent echocardiography 24 hours prior to and immediately after the marathon. All subjects were instructed not to exercise, to maintain their regular diet, ingest the same usual amount of liquids, and rest at least 8 hours a day in the period preceding the CPET.
  
  
  RESULTS
  The athletes completed the marathon in 221.5 (207; 250) minutes. In the post-marathon CPET, there was a significant reduction in peak oxygen consumption and peak oxygen pulse compared to the results obtained before the race (50.75 and 46.35 mL.kg-1 .min-1; 19.4 and 18.1 mL.btm, respectively). The echocardiography showed a significant reduction in the s' wave (inotropic marker), but no significant change in the E/e' ratio (lusitropic marker).
  
  
  CONCLUSIONS
  In amateur runners, the marathon seems to promote changes in the cardiopulmonary capacity identified within 4 days after the race, with a reduction in the cardiac contractility. Such changes suggest that some degree of "cardiac fatigue" can occur.
authors.affiliation: Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Ana Paula Rennó
authors.initials: AP
authors.lastname: Sierra
authors.affiliation: Grupo de Pesquisa em Cardiologia do Exercício, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.
authors.forename: Anderson Donelli
authors.initials: AD
authors.lastname: da Silveira
authors.affiliation: Seção de Cardioesporte, Instituto Dante Pazzanese de Cardiologia, São Paulo, SP, Brazil.
authors.forename: Ricardo Contesini
authors.initials: RC
authors.lastname: Francisco
authors.affiliation: Setor de Ecocardiografia, Instituto Dante Pazzanese de Cardiologia, São Paulo, SP, Brazil.
authors.forename: Rodrigo Bellios de Mattos
authors.initials: RB
authors.lastname: Barretto
authors.affiliation: Setor de Eletrofisiologia, Instituto Dante Pazzanese de Cardiologia, São Paulo, SP, Brazil.
authors.forename: Carlos Anibal
authors.initials: CA
authors.lastname: Sierra
authors.affiliation: Setor de Ergometria e Reabilitação, Instituto Dante Pazzanese de Cardiologia, São Paulo, SP, Brazil.
authors.forename: Romeu Sergio
authors.initials: RS
authors.lastname: Meneghelo
authors.affiliation: Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Maria Augusta Peduti Dal Molin
authors.initials: MA
authors.lastname: Kiss
authors.affiliation: Seção de Cardioesporte, Instituto Dante Pazzanese de Cardiologia, São Paulo, SP, Brazil.
authors.forename: Nabil
authors.initials: N
authors.lastname: Ghorayeb
authors.affiliation: Grupo de Pesquisa em Cardiologia do Exercício, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Stein
mesh_terms: D000328:Adult; D004452:Echocardiography; D005080:Exercise Test; D006321:Heart / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue / Q000502:physiology*; D009200:Myocardial Contraction / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology*; D012016:Reference Values; D012420:Running / Q000502:physiology*; D018709:Statistics, Nonparametric; D013997:Time Factors; D016276:Ventricular Function