title: Are there negative responders to exercise training among heart failure patients?
abstract: OBJECTIVE
  Aerobic exercise training has been used in patients with stable heart failure (HF) to reduce the risk of clinical events. However, due to patient heterogeneity, some patients may experience a decrease in functional capacity due to such training. The purpose of this study was to estimate the proportion of HF patients participating in a training program who had negative responses to such therapy and to compare them with a concurrent control group.
  
  
  METHODS
  Baseline and 3-month peak V˙O2 measurements were obtained on 1870 HF subjects who were randomized to receive either an exercise training program or a control program of usual care without exercise training. The exercise program consisted of supervised walking or stationary cycling 3 d·wk(-1) for 12 wk as well as a 2-d·wk(-1) home exercise program after completing 18 supervised sessions. A negative response was defined as a baseline-to-3-month decrease in peak V˙O2 of at least 5 mL·kg(-1) min(-1), which was two times the SD of the control group's change in peak V˙O2.
  
  
  RESULTS
  The mean ± SD change in peak V˙O2 in the exercise group and control group was 0.8 ± 2.5 mL·kg(-1)min(-1) and 0.2 ± 2.5 mL·kg(-1)min(-1), respectively (P < 0.001). The percentage of negative responders in the exercise and control groups was 0.9% and 2.3% (P = 0.02).
  
  
  CONCLUSIONS
  The low negative response rate in the exercise group combined with the slightly higher rate in the control group and equal variability in the exercise and control groups suggests that few if any subjects had training-related negative peak V˙O2 responses. These findings support current exercise recommendations for HF patients.
authors.affiliation: 1Office of Biostatistics Research, National Heart, Lung, and Blood Institute, Bethesda, MD; 2Division of Cardiovascular Medicine, Henry Ford Hospital, Detroit, MI; 3Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, Bethesda, MD; 4Department of Medicine, Duke University Medical Center, Durham, NC; 5Department of Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA; and 6Division of Cardiology, Albert Einstein College of Medicine, Bronx, NY.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Leifer
authors.forename: Clinton A
authors.initials: CA
authors.lastname: Brawner
authors.forename: Jerome L
authors.initials: JL
authors.lastname: Fleg
authors.forename: William E
authors.initials: WE
authors.lastname: Kraus
authors.forename: David J
authors.initials: DJ
authors.lastname: Whellan
authors.forename: Ileana L
authors.initials: IL
authors.lastname: Piña
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Keteyian
mesh_terms: D000328:Adult; D000368:Aged; D001642:Bicycling / Q000502:physiology; D005081:Exercise Therapy / Q000009:adverse effects*; D005260:Female; D006333:Heart Failure / Q000503:physiopathology* / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D016138:Walking / Q000502:physiology