title: Effect of acupuncture on heart rate variability: a systematic review.
abstract: OBJECTIVE
  To summarize all relevant trials and critically evaluate the effect of acupuncture on heart rate variability (HRV).
  
  
  METHODS
  This was a systematic review with meta-analysis. Keyword search was conducted in 7 databases for randomized controlled trials (RCTs). Data extraction and risk of bias were done.
  
  
  RESULTS
  Fourteen included studies showed a decreasing effect of acupuncture on low frequency (LF) and low frequency to high frequency ratio (LF/HF ratio) of HRV for nonhealthy subjects and on normalized low frequency (LF norm) for healthy subjects. The overall effect was in favour of the sham/control group for high frequency (HF) in nonhealthy subjects and for normalized high frequency (HF norm) in healthy subjects. Significant decreasing effect on HF and LF/HF ratio of HRV when acupuncture was performed on ST36 among healthy subjects and PC6 among both healthy and nonhealthy subjects, respectively.
  
  
  CONCLUSIONS
  This study partially supports the possible effect of acupuncture in modulating the LF of HRV in both healthy and nonhealthy subjects, while previous review reported that acupuncture did not have any convincing effect on HRV in healthy subjects. More published work is needed in this area to determine if HRV can be an indicator of the therapeutic effect of acupuncture.
authors.affiliation: Department of Health and Physical Education, The Hong Kong Institute of Education, 10 Lo Ping Road, Tai Po, New Territories, Hong Kong.
authors.forename: Joanne W Y
authors.initials: JW
authors.lastname: Chung
authors.affiliation: Department of Health and Physical Education, The Hong Kong Institute of Education, 10 Lo Ping Road, Tai Po, New Territories, Hong Kong.
authors.forename: Vincent C M
authors.initials: VC
authors.lastname: Yan
authors.affiliation: Chung Chi College, Chinese University of Hong Kong, Room 540, Sino Building, Shatin, Hong Kong.
authors.forename: Hongwei
authors.identifier: 0000-0002-2288-5394
authors.initials: H
authors.lastname: Zhang