Acupressure at Yin Tang: HRV and EEG

A study from 2011 exploring acupressure on Yin Tang, a follow up from a post  last week looking at press tacks on Yin Tang for preop anxiety reduction.  Their conclusion was that females were more likely to have a change in their HRV, but both genders experienced EEG changes.  Interesting!
“We concluded that acupressure on the Extra 1 point significantly reduced the EEG spectral entropy in both the genders, but affected the LF/HF ratio of HRV only in females.”
Evid Based Complement Alternat Med. 2011;2011:503698. doi:
The Influence of Acupressure at Extra 1 Acupuncture Point on the Spectral Entropy of the EEG and the LF/HF Ratio of Heart Rate Variability.
Arai YC, Ushida T, Matsubara T, Shimo K, Ito H, Sato Y, Wakao Y, Komatsu T.
Multidisciplinary Pain Centre, Aichi Medical University, School of Medicine, 21 Karimata, Nagakutecho, Aichigun, Aichi, 480-1195, Japan.
Abstract
Acupressure applied on the Extra 1 acupuncture point results in sedation, thereby reducing bispectral index (BIS) values. Mental status and hypnotic agents influence the autonomic nervous system. We hypothesized that acupressure at the Extra 1 point would induce sedation and change sympatho-parasympathetic nerve balance. We investigated the effect of acupressure at the Extra 1 point on the EEG spectral entropy values and heart rate variability (HRV). Forty-eight volunteers (24 males and 24 females) were randomly assigned to the control or Extra 1 group. The control group received acupressure at a sham point and the Extra 1 group received acupressure at the Extra 1 point. Acupressure was applied for 5 min. The record of the EEG spectral entropy values and HRV started 5 min before acupressure and stopped 5 min after acupressure. Acupressure significantly reduced the EEG spectral entropy values in both groups, but the values of the Extra 1 group were significantly smaller than those of the control group (P < .01). Acupressure significantly decreased the LF/HF ratio of HRV in both groups (P < .05). When divided upon gender, although acupressure tended to decrease the LF/HF ratio, the ratio significantly decreased during and after acupressure only in females of the Extra 1 group (P < .05). We concluded that acupressure on the Extra 1 point significantly reduced the EEG spectral entropy in both the genders, but affected the LF/HF ratio of HRV only in females.