Objectives: In this study, we investigated the short term effects of acupuncture on autonomic control of blood flow in healthy subjects. We also studied whether deqi (obtaining qi) sensations are correlated with these autonomic hemodynamic changes.
Methods: The experiment had a randomized, crossover design. Five healthy volunteers (age: 18-26 years) participated in this study. Acupuncture (2 Hz rotations for 10 seconds to 20 mm deep) was applied either to the acupuncture point SP3 or KI2 for 5 minutes. Non-invasively obtained continuous hemodynamic measurements of ultrasound Dopplerography were recorded at the radial artery before, during and after acupuncture stimulation. Cardiovascular autonomic tone was also recorded using power spectral analysis of heart rate variability. After acupuncture stimulation, the participants completed the acupuncture perception scales to measure the degree of deqi or pain they had experienced.
Results: Acupuncture stimulation to the acupuncture point SP3, when compared to the acupuncture point KI2, decreased the maximum systolic velocity. It also decreased low frequency component and increased high frequency component of heart rate variability, indicating that the decrease in systolic blood flow velocity was due to the increased parasympathetic response. Interestingly, warm, radiating and energetic feeling, which are related to deqi, had close correlations with the decrease in blood flow velocity.
Discussion: Acupuncture stimulation to the acupuncture point SP3 modulates the autonomic cardiovascular responses by enhancing parasympathetic function, and this may help to understand the therapeutic effects of acupuncture.