title: Heart rate variability biofeedback increases baroreflex gain and peak expiratory flow.
abstract: OBJECTIVE
  We evaluated heart rate variability biofeedback as a method for increasing vagal baroreflex gain and improving pulmonary function among 54 healthy adults.
  
  
  METHODS
  We compared 10 sessions of biofeedback training with an uninstructed control. Cognitive and physiological effects were measured in four of the sessions.
  
  
  RESULTS
  We found acute increases in low-frequency and total spectrum heart rate variability, and in vagal baroreflex gain, correlated with slow breathing during biofeedback periods. Increased baseline baroreflex gain also occurred across sessions in the biofeedback group, independent of respiratory changes, and peak expiratory flow increased in this group, independently of cardiovascular changes. Biofeedback was accompanied by fewer adverse relaxation side effects than the control condition.
  
  
  CONCLUSIONS
  Heart rate variability biofeedback had strong long-term influences on resting baroreflex gain and pulmonary function. It should be examined as a method for treating cardiovascular and pulmonary diseases. Also, this study demonstrates neuroplasticity of the baroreflex.
mesh_terms: D000328:Adult; D017704:Baroreflex / Q000502:physiology*; D001676:Biofeedback, Psychology / Q000502:physiology*; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D010366:Peak Expiratory Flow Rate; D011897:Random Allocation; D012064:Relaxation Therapy; D012119:Respiration; D011795:Surveys and Questionnaires; D014630:Vagus Nerve / Q000502:physiology*