title: Do cardiorespiratory variables predict the antinociceptive effects of deep and slow breathing?
abstract: Deep and slow breathing (DSB) is a central part of behavioral exercises used for acute and chronic pain management. Its mechanisms of action are incompletely understood.
  
  
  OBJECTIVE
  1) To test the effects of breathing frequency on experimental pain perception in a dose dependent fashion. 2) To test the effects of breathing frequency on cardiorespiratory variables hypothesized to mediate DSB analgesia. 3) To determine the potential of the cardiorespiratory variables to mediate antinociceptive DSB effects by regression analysis.
  
  
  METHODS
  Single-blind, randomized, crossover trial.
  
  
  METHODS
  Twenty healthy participants.
  
  
  METHODS
  Visually paced breathing at 0.14 Hz, 0.10 Hz, 0.06 Hz, and resting frequency.
  
  
  METHODS
  Cardiorespiratory variables: RR-interval (= 60 seconds/heart rate), standard deviation of the RR-interval (SDRR), and respiratory CO2 . Experimental pain measures: heat pain thresholds, cold pain thresholds, pain intensity ratings, and pain unpleasantness ratings.
  
  
  RESULTS
  1) There was no effect of DSB frequency on experimental pain perception. 2) SDRR and respiratory CO2 were significantly modulated by DSB frequency, while RR-interval was not. 3) Baseline-to-DSB and session-to-session differences in RR-interval significantly predicted pain perception within participants: Prolonged RR-intervals predicted lower pain ratings, while shortened RR-intervals predicted higher pain ratings. SDRR and respiratory CO2 were not found to predict pain perception.
  
  
  CONCLUSIONS
  The present study could not confirm hypotheses that the antinociceptive effects of DSB are related to changes in breathing frequency, heart rate variability, or hypoventilation/hyperventilation when applied as a short-term intervention. It could confirm the notion that increased cardiac parasympathetic activity is associated with reduced pain perception.
authors.affiliation: Departments of Experimental Psychology, University of Regensburg, Regensburg, Germany. matthias.zunhammer@klinik.uni-regensburg.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Zunhammer
authors.forename: Peter
authors.initials: P
authors.lastname: Eichhammer
authors.forename: Volker
authors.initials: V
authors.lastname: Busch
mesh_terms: D000328:Adult; D001945:Breathing Exercises / Q000379:methods*; D015928:Cognitive Behavioral Therapy / Q000379:methods*; D005260:Female; D064368:Healthy Volunteers; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D058748:Pain Perception / Q000502:physiology*; D017288:Pain Threshold / Q000502:physiology*; D063868:Patient Outcome Assessment; D011379:Prognosis; D012064:Relaxation Therapy / Q000379:methods*; D015203:Reproducibility of Results; D056152:Respiratory Rate / Q000502:physiology*; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D055815:Young Adult