title: Electrical stimulation of acupuncture points and blood pressure responses to postural changes: a pilot study.
abstract: BACKGROUND
  Application of transcutaneous electrical stimulation over acupuncture points (Acu-TENS) facilitates heart rate recovery after exercise and restores hemodynamic stability after open heart surgery. The role of Acu-TENS on cardiovascular parameters in response to postural changes has not been reported.
  
  
  OBJECTIVE
  To investigate (1) the effect of Acu-TENS on blood pressure responses to -10º head-down postural change and (2) whether such effects were associated with modulation by the autonomic nervous system.
  
  
  METHODS
  Sixteen healthy volunteers, mean age 22.8 (SD, 3.1) years, were subjected to a -10º head-down tilt from the supine position on 3 separate occasions and received in random order the following 3 intervention protocols for 40 minutes before the postural change: Acu-TENS (over bilateral acupuncture points, PC6), sham-TENS (TENS applied to the skin over the patellae), and control (no electrical output from the TENS device applied at PC6). Mean arterial pressure, large artery elasticity index, cardiac output, and heart rate were recorded and compared at different stimulation protocols in the supine and -10º head-down tilt positions. Spectral analysis of heart rate variability was used to determine any modulation by the autonomic nervous system.
  
  
  RESULTS
  Change in large artery elasticity index was observed only in the Acu-TENS group (P < .05) and mean arterial pressure appeared most stable during Acu-TENS. Autonomic nervous system modulation was not apparent with spectral analysis, irrespective of intervention. Sympathetic activity predominated in all positions.
  
  
  CONCLUSIONS
  Acu-TENS seems to reduce blood pressure changes with -10º head-down tilt with concomitant changes in arterial vessel tone.
authors.affiliation: Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong. Alice.Jones@polyu.edu.hk
authors.forename: Alice Y M
authors.initials: AY
authors.lastname: Jones
authors.forename: Y L
authors.initials: YL
authors.lastname: Kwan
authors.forename: Nathan T F
authors.initials: NT
authors.lastname: Leung
authors.forename: Rachel P W
authors.initials: RP
authors.lastname: Yu
authors.forename: Cindy M Y
authors.initials: CM
authors.lastname: Wu
authors.forename: Darren E R
authors.initials: DE
authors.lastname: Warburton
mesh_terms: D015669:Acupuncture Points; D001158:Arteries / Q000502:physiology; D001341:Autonomic Nervous System / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D004548:Elasticity / Q000502:physiology; D005260:Female; D018475:Head-Down Tilt / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D010865:Pilot Projects; D016683:Supine Position; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*