Osteopathic manipulative treatment and its relationship to autonomic nervous system activity as demonstrated by heart rate variability: a repeated measures study.
BACKGROUND
The relationship between osteopathic manipulative treatment (OMT) and the autonomic nervous system has long been acknowledged, but is poorly understood. In an effort to define this relationship, cervical myofascial release was used as the OMT technique with heart rate variability (HRV) as a surrogate for autonomic activity. This study quantifies that relationship and demonstrates a cause and effect.


METHODS
Seventeen healthy subjects, nine males and eight females aged 19-50 years from the faculty, staff, and students at Oklahoma State University Center for Health Sciences College of Osteopathic Medicine, acted as their own controls and received interventions, administered in separate sessions at least 24 hours apart, of cervical myofascial OMT, touch-only sham OMT, and no-touch control while at a 50-degree head-up tilt. Each group was dichotomized into extremes of autonomic activity using a tilt table. Comparisons were made between measurements taken at tilt and those taken at pre- and post-intervention in the horizontal.The variance of the spectral components of HRV, expressed as frequencies, measured the response to change in position of the subjects. Normalized low frequency (LF) and high frequency (HF) values, including LF/HF ratio, were calculated and used to determine the effect of position change on HRV.


RESULTS
Predominantly parasympathetic responses were observed with subjects in the horizontal position, while a 50-degree tilt provided a significantly different measure of maximum sympathetic tone (p < 0.001). Heart rate changed in all subjects with change in position; respirations remained constant. When OMT was performed in a sympathetic environment (tilt), a vagal response was produced that was strong enough to overcome the sympathetic tone. There was no HRV difference between sham and control in either the horizontal or tilt positions.


CONCLUSIONS
The vagal response produced by the myofascial release procedure in the maximally stimulated sympathetic environment could only have come from the application of the OMT. This demonstrates the association between OMT and the autonomic nervous system. The lack of significance between control and sham in all positions indicates that HRV may be a useful method of developing sham controls in future studies of OMT.


BACKGROUND
clinicaltrials.gov NCT00516984.
Henley
Charles E
CE
Oklahoma State University Center for Health Sciences Department of Pharmacology and Physiology, Tulsa, OK 74107, USA. bruce.benjamin@okstate.edu.
Ivins
Douglas
D
Mills
Miriam
M
Wen
Frances K
FK
Benjamin
Bruce A
BA