ABSTRACT
Objective: During acupuncture stimulation, autonomic nervous system (ANS) function changes toward being parasympathetic-dominant, with a transient decrease in heart rate (HR). The aim of this research was to determine the relationships between cortical relaxation and vigilance as observed on background electroencephalograms (EEGs), HR, and ANS function during deep acupuncture. Materials and Methods: This comparative study was conducted at Teikyo Heisei University, in Toshima-ku, Tokyo, Japan, with 27 healthy male volunteers. After resting for 20 minutes, the men received manual acupuncture at LI 10 on the left forearm for 2 minutes at a depth of 15-20 mm at a 1-Hz frequency while undergoing concurrent EEG and electrocardiography (ECG) monitoring. Each subject described his level of comfort during acupuncture. HR; power ratios (normalized units [n.u.]) of EEG alpha, beta, delta, and theta waves; and HR variability (HRV) indices were calculated. Results: In the subgroup who experienced discomfort, delta and theta n.u. were decreased while alpha n.u. were increased, indicating increased vigilance and decreased relaxation. In the subgroup who experienced comfort, there were no significant changes. HRV indices suggested parasympathetic-dominant changes in both subgroups. Weak correlations were observed between a decrease of theta n.u. and sympathetic-dominant changes in HRV indices. Conclusions: Alterations in background EEG activities were not the primary factors changing ANS function to parasympathetic-dominant and decreasing HR, but these alterations related to a weak secondary factor changing ANS function. EEG activity by which cortical relaxation and vigilance were represented was the weak secondary factor changing ANS function during acupuncture; the primary factor might be supraspinal reflection.
ABSTRACT
Objective: During acupuncture stimulation, heart rate (HR) transiently decreases and autonomic nervous system (ANS) function becomes parasympathetic-dominant. To clarify the effect of acupuncture sensations (pain, De Qi), the effects of deep acupuncture sensations on HR and ANS functions were determined. Materials and Methods: In this comparative study at Teikyo Heisei University, Tokyo, Japan, 40 healthy, male student volunteers rested for 20 minutes before undergoing manual acupuncture to the Shousanli (LI 10) acupoint on the left forearm for 2 minutes at a frequency of 1 Hz, with concurrent electrocardiography. Depth of stimulation was 15-20 mm. These subjects described their subjective acupuncture sensations. Calculations were performed, using HR variability analysis to find HR and low-frequency (LF) normalized units (nu), the ratio of LF components to total components (as an index of sympathetic nervous system function), high-frequency (HF)nu, the ratio of HF components to total components (as an index of parasympathetic nervous system function), and LF/HF (as an index of sympathetic and parasympathetic balance). Results: For the final analysis, data were available for 32 subjects. Compared to before acupuncture, HR decreased during acupuncture. HR decreased when no acupuncture sensations or when weak De Qi sensations were perceived, and remained unchanged when acupuncture sensations without De Qi or strong De Qi were perceived. LFnu decreased, HFnu increased, and LF/HF decreased, regardless of pain or De Qi. Conclusions: Acupuncture stimulation reduced HR even without De Qi sensations and caused ANS function to be parasympathetic-dominant, irrespective of the perception of acupuncture sensations.
ABSTRACT
Objective: Human studies have demonstrated that heart rate (HR) decreases during acupuncture stimulation, and pharmacologic studies have shown that this autonomic nervous system (ANS) response is parasympathetic-dominant. It has become clear that significant changes occur in the ANS after acupuncture, based on HR variability (HRV). However, it is inconclusive, according to HRV analysis, if acupuncture induces a significant change in autonomic function during stimulation. The aim of this study was to investigate ANS function using HRV analysis during HR reduction induced by manual acupuncture stimulation to the muscles. Materials and Methods: In this study, electrocardiograms of 25 adult men were analyzed. After resting for 20 minutes, participants underwent 15-20-mm deep acupuncture stimulation at the Shousanli (LI 10) point at 1 Hz for 2 minutes. Instantaneous HR was recorded. The index of parasympathetic nervous activity high-frequency (HF) normalized units (HFnu) and the ratio of sympathovagal balance (low frequency [LF]/HF) were calculated by HRV analysis. Results: HR during acupuncture was significantly lower, compared to HR both before and after acupuncture. HFnu during acupuncture were significantly higher, compared to HFnu both before and after acupuncture. The LF/HF ratio during acupuncture was significantly lower, compared to the ratio before acupuncture, and remained low after acupuncture, compared to before acupuncture. Conclusions: Acupuncture stimulation to the muscle can effectively reduce HR, increase HFnu, and decrease LF/HF that depends on autonomic regulation of both sympathovagal balances.
