Changes in heart rate variability (HRV) during low level laser-needle acupuncture

Background: Experimental and clinical studies postulate a neurobiological mechanism of acupuncture by modulating central pain systems, neurohormones and -transmitters. It seems to be quite likely that the autonomic nervous system (ANS) plays an important mediating role in this neuromodulation. Aim: In measuring heart rate variability (HRV), as a non-invasive approach to the ANS-function, the object of this study was to monitor probable acupuncture-induced changes of autonomic balance. The innovative technology of laser-needle acupuncture offers for the first time a stimulation method which fulfils the demands on a placebocontrolled acupuncture trial not requiring controversial sham acupuncture. Method: 19 healthy voluntary subjects underwent 3 treatments in randomized sequence, consisting of placebo-, 1-point-(PC 6) and simultaneous 3-point-(PC 6, LR 3, SI 3) laser-needle-stimulation over 20 minutes. Before, during and after placebo-/verum laser-needle acupuncture, HRV-data for normalized HF(high frequency)-and LF(low frequency)-Power (nHF, nLF) and their quotient nLF/nHF obtained by power spectrum analysis (FFT), were measured and analyzed statistically at 5 different time points (ANOVA repeated measures, p < 0,05). Results: During both verum applications, the 1-point-(PC 6) as well as the simultaneous 3-point-(PC 6, LR 3, SI 3) laser-needle stimulation, significant changes of the ANS-activity were found in comparison to the placebo application. The most significant modification of HRV was an increase of nHF (p < 0,05 (PC 6), p < 0,0001 (PC 6, LR 3, SI 3)) as an expression of growing vagal activity during acupuncture. Conclusion: Laser-needle acupuncture causes in 1-point-stimulation (PC 6) as well as in simultaneous 3-point-stimulation (PC 6, LR 3, SI 3) significant changes in HRV in comparison to placebo application. HRV-monitoring seems to be a suitable approach in exploration of acupuncture-induced changes of ANS and could possibly be established in combination with laser needle acupuncture as a standard for further scientific and clinical acupuncture investigations which are greatly needed.