title: Correlates of Exercise Self-efficacy in a Randomized Trial of Mind-Body Exercise in Patients With Chronic Heart Failure.
abstract: OBJECTIVE
  Exercise self-efficacy is one of the strongest predictors of physical activity behavior. Prior literature suggests that tai chi, a mind-body exercise, may increase self-efficacy; however, this is not extensively studied. Little is known about the factors associated with development of exercise self-efficacy in a population with heart failure.
  
  
  METHODS
  We utilized data from a randomized controlled trial of 12 weeks of group tai chi classes versus education in patients with chronic heart failure (n = 100). Multivariable linear regression was used to explore possible correlates of change in exercise self-efficacy in the entire sample and in the subgroup who received tai chi (n = 50). Covariates included baseline quality of life, social support, functional parameters, physical activity, serum biomarkers, sociodemographics, and clinical heart failure parameters.
  
  
  RESULTS
  Baseline 6-minute walk (β=-0.0003, SE = 0.0001, P = .02) and fatigue score (β= 0.03, SE = 0.01, P = .004) were significantly associated with change in self-efficacy, with those in the lowest tertile for 6-minute walk and higher tertiles for fatigue score experiencing the greatest change. Intervention group assignment was highly significant, with self-efficacy significantly improved in the tai chi group compared to the education control over 12 weeks (β= 0.39, SE = 0.11, P < .001). In the tai chi group alone, lower baseline oxygen uptake (β=-0.05, SE = 0.01, P = .001), decreased mood (β=-0.01, SE = 0.003, P = .004), and higher catecholamine level (epinephrine β= 0.003, SE = 0.001, P = .005) were significantly associated with improvements in self-efficacy.
  
  
  CONCLUSIONS
  In this exploratory analysis, our initial findings support the concept that interventions like tai chi may be beneficial in improving exercise self-efficacy, especially in patients with heart failure who are deconditioned, with lower functional status and mood.
authors.affiliation: Division of General Medicine and Primary Care, Department of Medicine, Beth Israel Deaconess Medical Center, Brookline, Massachusetts (Drs Yeh and Davis and Ms Mu); and Osher Center for Integrative Medicine, Harvard Medical School (Dr Wayne) and Division of Preventive Medicine, Brigham and Women's Hospital (Dr Wayne), Boston, Massachusetts.
authors.forename: Gloria Y
authors.initials: GY
authors.lastname: Yeh
authors.forename: Lin
authors.initials: L
authors.lastname: Mu
authors.forename: Roger B
authors.initials: RB
authors.lastname: Davis
authors.forename: Peter M
authors.initials: PM
authors.lastname: Wayne
mesh_terms: D000339:Affect; D000368:Aged; D002908:Chronic Disease; D004837:Epinephrine / Q000097:blood; D015444:Exercise / Q000502:physiology / Q000523:psychology*; D005080:Exercise Test; D017079:Exercise Tolerance; D005221:Fatigue / Q000209:etiology; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D010353:Patient Education as Topic; D011788:Quality of Life; D020377:Self Efficacy; D011795:Surveys and Questionnaires; D026302:Tai Ji / Q000523:psychology*
chemical_list: D004837:Epinephrine