title: Effects of breathing frequency on the heart rate deceleration capacity and heart rate acceleration capacity.
abstract: OBJECTIVE
  The deceleration capacity (DC) and acceleration capacity (AC) of heart rate as well as the respiratory rate predict outcome after acute myocardial infarction. We evaluated the relation between breathing frequency and both DC and AC, as well as the difference between them.
  
  
  METHODS
  We studied fourteen healthy young adults who breathed spontaneously and controlled their breathing to rates of 0.1, 0.2, 0.3, and 0.4 Hz in a supine position. A 5-min R-R interval time series without movement artifacts or ectopic beats was obtained from each studied period and scanned to identify the anchor points that were characterized by a value longer or shorter than the preceding value. Averaged changes of R-R intervals surrounding the deceleration and acceleration anchors were calculated as DC and AC, respectively.
  
  
  RESULTS
  The magnitudes of DC and AC increased progressively as breathing frequency decreased (Both p < 0.001 by one-way repeated-measures analysis of variance). The magnitude of DC was larger than the magnitude of AC during 0.1-Hz breathing (95 % confidence interval of their difference: 1.7-9.7 ms), while the difference between them reduced to near zero at higher frequencies.
  
  
  CONCLUSIONS
  Slow breathing enhances the magnitudes of DC and AC simultaneously under the conditions used in this study. The increase in the magnitude of DC is significantly greater than that of AC.
authors.affiliation: Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Yong-Ping
authors.initials: YP
authors.lastname: Wang
authors.affiliation: Institute of Brain Science, National Yang-Ming University, No. 155, Sec. 2, Li-Nong Street, Taipei, 11221, Taiwan.|Sleep Research Center, National Yang-Ming University, Taipei, Taiwan.|Brain Research Center, National Yang-Ming University, Taipei, Taiwan.|Department of Education and Research, Taipei City Hospital, Taipei, Taiwan.|Institute of Translational and Interdisciplinary Medicine, National Central University, Taoyuan, Taiwan.|Chief of Division of Translational Medicine, Stroke and Neurovascular Center, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Terry B J
authors.initials: TB
authors.lastname: Kuo
authors.affiliation: Institute of Brain Science, National Yang-Ming University, No. 155, Sec. 2, Li-Nong Street, Taipei, 11221, Taiwan.|Sleep Research Center, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Chun-Ting
authors.initials: CT
authors.lastname: Lai
authors.affiliation: Institute of Brain Science, National Yang-Ming University, No. 155, Sec. 2, Li-Nong Street, Taipei, 11221, Taiwan. cchyang@ym.edu.tw.|Sleep Research Center, National Yang-Ming University, Taipei, Taiwan. cchyang@ym.edu.tw.|Brain Research Center, National Yang-Ming University, Taipei, Taiwan. cchyang@ym.edu.tw.|Department of Education and Research, Taipei City Hospital, Taipei, Taiwan. cchyang@ym.edu.tw.
authors.forename: Cheryl C H
authors.initials: CC
authors.lastname: Yang
mesh_terms: D000054:Acceleration; D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology*; D003654:Deceleration; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D012119:Respiration; D056152:Respiratory Rate / Q000502:physiology*; D065809:Respiratory Sinus Arrhythmia / Q000502:physiology*; D055815:Young Adult
keywords: Acceleration; Deceleration; Heart rate; Respiration