Immediate Effects of Dry Needling on the Autonomic Nervous System and Mechanical Hyperalgesia: A Randomized Controlled Trial

Background: Dry needling (DN) is often used for the treatment of muscle pain among physiotherapists. However, little is known about the mechanisms of action by which its effects are generated. The aim of this randomized controlled trial was to determine if the use of DN in healthy subjects activates the sympathetic nervous system, thus resulting in a decrease in pain caused by stress. Methods: Sixty-five healthy volunteer subjects were recruited from the University of Alcala, Madrid, Spain, with an age of 27.78 (SD = 8.41) years. The participants were randomly assigned to participate in a group with deep DN in the adductor pollicis muscle or a placebo needling group. The autonomic nervous system was evaluated, in addition to local and remote mechanical hyperalgesia. Results: In a comparison of the moment at which the needling intervention was carried out with the baseline, the heart rate of the dry needling group significantly increased by 20.60% (SE = 2.88), whereas that of the placebo group increased by 5.33% (SE = 2.32) (p = 0.001, d = 1.02). The pressure pain threshold showed significant differences between both groups, being significantly higher in the needling group (adductor muscle p = 0.001; d = 0.85; anterior tibialis muscle p = 0.022, d = 0.58). Conclusions: This work appears to indicate that dry needling produces an immediate activation in the sympathetic nervous system, improving local and distant mechanical hyperalgesia.