title: Does Stroke Volume Increase During an Incremental Exercise? A Systematic Review.
abstract: BACKGROUND
  Cardiac output increases during incremental-load exercise to meet metabolic skeletal muscle demand. This response requires a fast adjustment in heart rate and stroke volume. The heart rate is well known to increase linearly with exercise load; however, data for stroke volume during incremental-load exercise are unclear. Our objectives were to (a) review studies that have investigated stroke volume on incremental load exercise and (b) summarize the findings for stroke volume, primarily at maximal-exercise load.
  
  
  METHODS
  A comprehensive review of the Cochrane Library's, Embase, Medline, SportDiscus, PubMed, and Web of Sci-ence databases was carried out for the years 1985 to the present. The search was performed between February and June 2014 to find studies evaluating changes in stroke volume during incremental-load exercise. Controlled and uncontrolled trials were evaluated for a quality score.
  
  
  RESULTS
  The stroke volume data in maximal-exercise load are inconsistent. There is evidence to hypothesis that stroke volume increases during maximal-exercise load, but other lines of evidence indicate that stroke volume reaches a plateau under these circumstances, or even decreases.
  
  
  CONCLUSIONS
  The stroke volume are unclear, include contradictory evidence. Additional studies with standardized reporting for subjects (e.g., age, gender, physical fitness, and body position), exercise test protocols, and left ventricular function are required to clarify the characteristics of stroke volume during incremental maximal-exercise load.
authors.affiliation: Universidade Federal de São Paulo, Laboratório de Fisiologia e Fisiopatologia Cardíaca, São Paulo, SP, Brazil.
authors.forename: Stella S
authors.initials: SS
authors.lastname: Vieira
authors.affiliation: Universidade Federal de São Paulo, Laboratório de Fisiologia e Fisiopatologia Cardíaca, São Paulo, SP, Brazil.
authors.forename: Brunno
authors.initials: B
authors.lastname: Lemes
authors.affiliation: Universidade Nove de Julho, Programa de Pós-Graduação em Biofotônica Aplicada a Ciências da Saúde, São Paulo, SP, Brazil.
authors.forename: Paulo
authors.initials: P
authors.lastname: de T C de Carvalho
authors.affiliation: Universidade Nove de Julho, Programa de Pós-Graduação em Biofotônica Aplicada a Ciências da Saúde, São Paulo, SP, Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: N de Lima
authors.affiliation: Laboratorio de Fisiologia Transacional dos Programas de Pos Graduacao em Educacao Fisica e Ciências do En-velhecimento, São Paulo, SP, Brasil.
authors.forename: Danilo
authors.initials: D
authors.lastname: S Bocalini
authors.affiliation: Universidade Nove de Julho, Programa de Pós-Graduação em Medicina, São Paulo, SP, Brazil.
authors.forename: José
authors.initials: J
authors.lastname: A S Junior
authors.affiliation: Universidade Federal do Mato Grosso, Programa de Mestrado em Educação Física, Cuiabá, MT, Brazil.
authors.forename: Gisela
authors.initials: G
authors.lastname: Arsa
authors.affiliation: Universidade Nove de Julho, Programa de Pós-Graduação em Biofotônica Aplicada a Ciências da Saúde, São Paulo, SP, Brazil.
authors.forename: Cezar
authors.initials: C
authors.lastname: A Casarin
authors.affiliation: Laboratorio de Fisiologia Transacional dos Programas de Pos Graduacao em Educacao Fisica e Ciências do En-velhecimento, São Paulo, SP, Brasil.
authors.forename: Erinaldo
authors.initials: E
authors.lastname: L Andrade
authors.affiliation: Universidade Nove de Julho, Programa de Pós-Graduação em Biofotônica Aplicada a Ciências da Saúde, São Paulo, SP, Brazil.
authors.forename: Andrey
authors.initials: A
authors.lastname: J Serra
keywords: Aerobic exercise; cardiac function; heart physiology; incremental exercise; maximal-exercise load; stroke volume