title: Exercise training for heart failure patients improves respiratory muscle endurance, exercise tolerance, breathlessness, and quality of life.
abstract: OBJECTIVE
  Increased respiratory muscle endurance and peak oxygen consumption (VO(2peak)) induced by respiratory muscle training support the relationship between respiratory muscle function and exercise capacity in patients with heart failure. This raises the question whether exercise-training results in increased respiratory muscle function contributing to an increased exercise tolerance, a decreased perception of breathlessness, and an improved quality of life.
  
  
  METHODS
  Prospective cohort analysis was completed on 24 patients with New York Heart Association (NYHA) Class III heart failure [18 men, 6 women; aged = 64 (SD 7.9) years; percent ejection fraction (%EF) = 24.0 (SD 7.8)]. Maximal sustainable ventilatory capacity (MSVC), submaximal and peak exercise responses, perception of breathlessness, and quality of life were measured before (baseline) and after (end of study) 12 weeks of exercise training.
  
  
  RESULTS
  As a result of exercise training, VO(2peak) (P=.01) and MSVC (P<.001) increased, with MSVC contributing to a larger proportion of the variability for VO(2peak) at study completion (r=0.57 vs 0.42). Although stroke volume did not increase beyond exercise at 25 W and did not change with exercise training, ventilation decreased during exercise (P<.05), perception of breathing difficulty (P<.05) was reduced, and quality of life was enhanced (P=.008).
  
  
  CONCLUSIONS
  Despite no increase in cardiac output and stroke volume, respiratory muscle endurance improved with exercise training, contributing to increased exercise capacity, decreased breathlessness, and decreased perception of breathlessness. Practical implications can include less frequent rest periods and fatigue, greater confidence, maintenance of independence, and enhanced quality of life.
authors.affiliation: Department of Cardiology, Geisinger Medical Center, Danville, PA 17822-2160, USA. tmcconnell@geisinger.edu
authors.forename: Timothy R
authors.initials: TR
authors.lastname: McConnell
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Mandak
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Sykes
authors.forename: Henry
authors.initials: H
authors.lastname: Fesniak
authors.forename: Himadri
authors.initials: H
authors.lastname: Dasgupta
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D015331:Cohort Studies; D004417:Dyspnea / Q000517:prevention & control*; D005081:Exercise Therapy; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000534:rehabilitation*; D006334:Heart Function Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance; D011336:Probability; D011446:Prospective Studies; D011788:Quality of Life; D012129:Respiratory Function Tests; D012132:Respiratory Muscles / Q000502:physiology*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index