Tim Hideaki Tanaka, Ph.D.
World Health Organization (WHO) Congress on Traditional Medicine, Beijing, China, 2008
Objectives: The importance of paying attention to a patient’s respiration during acupuncture was emphasized as far back as 2000 years ago in Huangdi Neijing. More recently, superficial acupuncture, when stimulated in phase with expiration rhythm, has been shown to increase parasympathetic activity. A heart rate variability biofeedback (HRV-BFB) method has been increasingly utilized in the field of applied psychophysiology. The method is designed to train patients to breathe at a specific rate in order to create slow heart rate oscillation and augment HRV. HRV-BFB has been shown to increase baroreceptor function and has been shown to be efficacious in the treatment of various diseases related to autonomic dysfunctions. There are however, a couple of issues to consider when attempting to incorporate HRV-BFB during acupuncture treatment procedure. First, because conventional BFB methods are typically done by letting patients obtain visual feedback from a computer screen, treatment position is generally limited to a seated position. Second, there is a potential activation of sympathetic nerve and EEG beta waves due to focusing on the computer screen. For practical incorporation of HRV-BFB during an acupuncture session, an audio CD was created in order to more naturally guide patient’s breathing towards the targeted frequency (HRV Trainer CD, non-commercial, 2002). A preliminary study was conducted to test subjects’ compliance and response with the CD guided breathing training as a part of an exploration to enhance the autonomic effect of acupuncture.
Methods: An audio CD containing voice commands, ocean sounds and classical music was designed. Four healthy subjects were seated with their backs supported. The ECG signals were obtained through the electrodes using a standard lead II configuration. In addition, strain gauge was attached to the subjects’ chests to monitor their respiration. After a 5 minute resting period, subjects were asked to breathe at the rate of 12 breathes per minute paced by visual cues on the computer screen for 5 minutes. Then the screen was masked and the CD was played. After 35 minutes, the CD was turned off and the computer screen was again shown to the subjects for the paced breathing. ECG signals were recorded continuously during the entire procedure using Biopac MP 150 with a sampling rate of 1000 Hz. Power spectral analysis was conducted by means of Fast Fourier Transform based on the stored ECG R-R interval data (Biosignals, Finland). The power spectra were divided into two frequency bands of interest: LF (0.04 to 0.15 Hz), and HF (0.15 to 0.4 Hz).
Results and Discussion: An observation of respiration rate indicated that subjects had good compliance following the voice and wave cues. In regards to frequency domain HRV analysis, LF power sharply increased as subjects started to hear the CD through headphones. LF increase was greatest and most steady during the CD track with ocean wave sounds; however the increase remained also during the tracks with only classical music. In contrast to noticeable LF changes, the subjects HF components during the CD session were relatively very low. The power of the LF component is considered to be a marker of both sympathetic and vagal modulation, and the HF component is considered to reflect the vagal activity . It should be noted however that HF is associated with vagal modulation of the heart only when a subject’s respiration rate is within the HF range (between 9 to 24 cycles per minute). During the CD session, subjects were breathing much slower than HF range, approximately at the rate of 6 breaths per minute, as intended. Therefore, the respiratory linked HRV, which is referred to as respiratory sinus arrhythmia and is usually seen in the HF range, was shifted to the lower frequency range. Overall, as indicated by total power spectra during each period, the heart rate was oscillating with much greater amplitude during the CD session compared to the rest period and the controlled respiration period (at 12 breaths per minute). This suggests that the CD guided auditory breathing methods induced quite a different autonomic state compared to the period of quiet rest or relaxation.
Conclusion: The HRV power spectra indicate that the subject’s baroreceptor activity and autonomic reflexes were highly enhanced during CD guided breathing. Administering acupuncture when a patient’s physiological state is in such a balance may hold great potential for profound clinical outcomes. Since 2002 in our facility, we have been utilizing combined acupuncture and HRV-BFB based slow breathing application, in an attempt to further stimulate the autonomic nervous system. Our patients are directed to perform rhythmic breathing, with the aid of the CD, while needles are inserted. HRV is recorded during the session to monitor the compliance and the physiological response. We have noted positive effects on various conditions; especially on disorders related to disrupted autonomic and biological rhythms.
1. Mori, H., et al., Pupillary response induced by acupuncture stimulation. Acupunct Med, 2008. 26(2): p. 79-86.
2. Lehrer, P.M., E. Vaschillo, and B. Vaschillo, Resonant frequency biofeedback training to increase cardiac variability: rationale and manual for training. Appl Psychophysiol Biofeedback, 2000. 25(3): p. 177-91.
3. Lehrer, P.M., et al., Heart rate variability biofeedback increases baroreflex gain and peak expiratory flow. Psychosom Med, 2003. 65(5): p. 796-805.
4. Tanaka, T.H., The creation and efficacy of a HRV-Autonomic Trainer CD in assisting heart rate variability biofeedback training: preliminary report. Appl Psychophysiol Biofeedback, 2003. 28(4): p. 326.
5.Task Force, Heart Rate Variability: Standards of Measurement, Physiological Interpretation, and Clinical Use. Circulation, 1996. 93(5): p. 1043-1065.