title: Effect of continuous and interval exercise training on the PETCO2 response during a graded exercise test in patients with coronary artery disease.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the following: 1) the effects of continuous exercise training and interval exercise training on the end-tidal carbon dioxide pressure (PETCO2) response during a graded exercise test in patients with coronary artery disease; and 2) the effects of exercise training modalities on the association between PETCO2 at the ventilatory anaerobic threshold (VAT) and indicators of ventilatory efficiency and cardiorespiratory fitness in patients with coronary artery disease.
  
  
  METHODS
  Thirty-seven patients (59.7 + 1.7 years) with coronary artery disease were randomly divided into two groups: continuous exercise training (n = 20) and interval exercise training (n = 17). All patients performed a graded exercise test with respiratory gas analysis before and after three months of the exercise training program to determine the VAT, respiratory compensation point (RCP) and peak oxygen consumption.
  
  
  RESULTS
  After the interventions, both groups exhibited increased cardiorespiratory fitness. Indeed, the continuous exercise and interval exercise training groups demonstrated increases in both ventilatory efficiency and PETCO2 values at VAT, RCP, and peak of exercise. Significant associations were observed in both groups: 1) continuous exercise training (PETCO2VAT and cardiorespiratory fitness r = 0.49; PETCO2VAT and ventilatory efficiency r = -0.80) and 2) interval exercise training (PETCO2VAT and cardiorespiratory fitness r = 0.39; PETCO2VAT and ventilatory efficiency r = -0.45).
  
  
  CONCLUSIONS
  Both exercise training modalities showed similar increases in PETCO2 levels during a graded exercise test in patients with coronary artery disease, which may be associated with an improvement in ventilatory efficiency and cardiorespiratory fitness.
authors: TotalCor Amil Hospital São Paulo, São Paulo, SP, Brazil.
authors: Enéas A
authors: EA
authors: Rocco
authors: Danilo M L
authors: DM
authors: Prado
authors: Alexandre G
authors: AG
authors: Silva
authors: Jaqueline M A
authors: JM
authors: Lazzari
authors: Pedro C
authors: PC
authors: Bortz
authors: Débora F M
authors: DF
authors: Rocco
authors: Carla G
authors: CG
authors: Rosa
authors: Valter
authors: V
authors: Furlan
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis*; D003324:Coronary Artery Disease / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D012016:Reference Values; D012129:Respiratory Function Tests / Q000379:methods*; D013997:Time Factors
chemical_list: D002245:Carbon Dioxide