Sympathetic Nervous System Responses to Acupuncture and Non-Penetrating Sham Acupuncture in Experimental Forearm Pain: A Single-Blind Randomised Descriptive Study

Abstract

Objective To quantify the sympathetic nervous system response to acupuncture and non-penetrating sham acupuncture in volunteers with pain. Methods A single-blind, randomised controlled study of 36 healthy adults with no recent participation in forearm strengthening or occupations involving repeated forceful wrist motion was carried out. A fatiguing wrist extension exercise protocol was completed to induce delayed onset muscle soreness. Group 1 received no treatment, group 2 a single session of acupuncture and group 3 a single session of sham acupuncture. Outcomes included skin conductance, skin temperature and perfusion measured for 20 min before treatment, during the 15 min treatment and for 10 min after treatment. Results The acupuncture group showed a significant increase from baseline in ipsilateral perfusion (135%) and bilateral skin conductance (144 and 146%) and a significant decrease from baseline in bilateral distal skin temperature (98%). The acupuncture and sham acupuncture groups showed decreased ipsilateral proximal skin temperature. Conclusions Acupuncture appears to activate the sympathetic nervous system, indicated by a bilateral increase in skin conductance and a bilateral decrease in distal skin temperature after needle insertion. The unilateral increase in perfusion near the needle site seen with acupuncture treatment may be due to local circulatory, rather than systemic, control.