title: Low intensity exercise training in patients with chronic heart failure.
abstract: OBJECTIVE
  The present study was designed to evaluate whether a specific program of low intensity exercise training may be sufficient to improve the exercise tolerance of patients with chronic heart failure.
  
  
  BACKGROUND
  Recent studies have shown that exercise training can improve exercise tolerance in patients with stable chronic heart failure, mainly through peripheral adaptations. These changes have been observed with exercise regimens at intensities of 70% to 80% of peak oxygen uptake and > 8 weeks.
  
  
  METHODS
  We studied 27 patients (23 men, 4 women; mean [+/- SD] age 57 +/- 6 years) with mild chronic heart failure. We classified patients into two groups: trained group and untrained group. The trained group underwent a low intensity (40% of peak oxygen uptake) training program three times/week for 8 weeks. The untrained group performed no exercise.
  
  
  RESULTS
  An increase in peak oxygen uptake (17%, p < 0.0001), lactic acidosis threshold (20%, p < 0.0002) and peak work load (21%, p < 0.0002) were obtained in the trained group only. Cardiac output and stroke volume were unchanged. A high correlation was found between the increases in peak oxygen uptake and volume density of mitochondria of vastus lateralis muscle (r = 0.77, p < 0.0002).
  
  
  CONCLUSIONS
  Patients with stable chronic heart failure can achieve significant improvement in functional capacity from a low intensity exercise training regimen. The mechanism responsible for this favorable effect involves an increase in mitochondrial density, which reflects an improvement in oxidative capacity of trained skeletal muscles.
authors.affiliation: Divisione di Cardiologia I, Ospedale Cardiologico G. M. Lancisi, Ancona, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Belardinelli
authors.forename: D
authors.initials: D
authors.lastname: Georgiou
authors.forename: V
authors.initials: V
authors.lastname: Scocco
authors.forename: T J
authors.initials: TJ
authors.lastname: Barstow
authors.forename: A
authors.initials: A
authors.lastname: Purcaro
mesh_terms: D015308:Anaerobic Threshold / Q000502:physiology; D001706:Biopsy; D004452:Echocardiography; D005080:Exercise Test; D005081:Exercise Therapy / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000534:rehabilitation*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008931:Mitochondria, Muscle / Q000378:metabolism / Q000473:pathology; D018482:Muscle, Skeletal / Q000473:pathology; D010101:Oxygen Consumption / Q000502:physiology