Acupuncture attenuates exercise-induced increases in skin sympathetic nerve activity

To identify the effect of acupuncture on skin sympathetic nerve activity (SSNA), 17 healthy subjects (7 male and 10 female) underwent LI4 acupuncture and sham needle insertion during resting or elevated SSNA conditions. In Protocol 1 (resting SSNA), subjects received a 10 min sham followed by 10 min of LI4 acupuncture during resting conditions. In Protocol 2 (elevated SSNA), subjects performed 10 min of submaximal intermittent handgrip (2:4s work to rest interval at 37±3% of maximal voluntary contraction) during sham and LI4 acupuncture conditions. SSNA (peroneal nerve microneurography), heart rate (ECG), and mean arterial blood pressure (finger photoplethysmography) were measured and normalized to baseline. SSNA, heart rate, and mean arterial blood pressure were not significantly altered during resting conditions (Protocol 1). During handgrip (Protocol 2), SSNA significantly increased with the sham treatment (+15.3±8.8, +11.1±5.9, and +24.3±13.0% at minutes 1, 5, and 10, respectively), while LI4 acupuncture attenuated this increase (-1.6±7.6, 0.0±4.3, and +2.2±11.2% at minutes 1, 5, and 10, respectively). Heart rate and mean arterial blood pressure increased during handgrip (Protocol 2), but no differences were observed between sham and LI4 acupuncture treatments. These results suggest that acupuncture does not affect resting SSNA in healthy subjects, however if SSNA is acutely elevated above baseline levels, acupuncture has the capacity to attenuate the increased SSNA.