Osteopathic Manipulative Treatment and Its Relationship to Autonomic Nervous System Activity as Demonstrated by Heart Rate Variability Charles E. Henley, DO, MPH, FAAFP University of Oklahoma College of Medicine, Tulsa Department of Family Medicine, Tulsa OK Bruce A. Benjamin, PhD Oklahoma State University College of Osteopathic Medicine, Department of Pharmacology/Physiology, Tulsa OK

Introduction Validation of OMT largely observational, based on patient outcomes Little quantitative data evaluating relationship between manipulation and ANS Lack of ability to accurately measure autonomic activity directly Heart rate variability (HRV) has developed into noninvasive, commonly used method to measure autonomic activity 1,2

Objective To study the relationship between Osteopathic manipulative therapy (OMT) and the autonomic nervous system using heart rate variability (HRV) as a surrogate for autonomic activity.

Methodology Recruitment 28 OSU COM students, staff and faculty Inclusion criteria Written informed consent Normal, healthy adults age years Normal ECG Normal blood pressure (as per JNC-7 criteria)

Methodology Exclusion criteria Chronic disease conditions Pregnancy Smoker PVC exceeding 20% total heart beats Resting supine heart rate >75 bpm or <45 bpm Blood pressure 140 mmHg Failure of heart rate to increase with passive tilt Long-distance runners, other conditioned athletes

Methodology General Study Design: Repeated Measures Each subject acted as own control Random assignment to first group 30 minute study protocol 10 minutes Horizontal 1 (H1) 10 minutes 50 degree head-up Tilt (T)  Sham or OMT 10 minutes Horizontal 2 (H2) Continuous recording of ECG and respiration data

Methodology Study groups Control: Positional changes only (H1, Tilt, H2) Sham: Positional changes with operator’s hands in OMT treatment position without applied treatment Treatment: OMT – Cervical myofascial release Positional changes with OMT for 2 minutes in 50 degree head-up position

Methodology Data Collection and Analysis R-R intervals determined by R-wave peak detection algorithm Frequency analysis of HRV by LF, HF, LF/HF Within subjects repeated measure t-tests and repeated ANOVA pairings Repeated ANOVA using multivariate approach Power analysis: N=14 alpha=0.05, beta=0.80 Estimated 25% difference in group mean ratios Standard deviation = 2.6

Results 17 of 28 subjects (61%) completed study 9 men and 8 women No adverse effects of the study

Results Heart Rate Significant increase (p<0.001) with position change from H1 to Tilt within all groups (*) In Tilt, HR for OMT was significantly decreased (p<0.001) from Control and Sham Returned to baseline for all groups upon return to horizontal

Results Low Frequency Significant increase (p<0.001) with positional change from H1 to Tilt in Control and Sham Significantly less increase in OMT compared to Control and Sham Returned to baseline for all groups upon return to horizontal

Results High Frequency (HF) In Tilt, HF in Control and Sham groups was significantly decreased compared to H1 Change with OMT was not as great compared to Control and Sham Returned to baseline for all groups upon return to horizontal

Results LF/HF Ratio Tilt significantly increased ratio in Control and Sham due to increase in LF and decrease in HF OMT significantly reduced ratio in Tilt position Ratio returned to baseline upon subject return to horizontal Ratio for OMT at Tilt was statistically different (p<0.001) from Control and Sham at Tilt

Results

Respiration Continuously measured throughout study No change in respiration with body position Rate of respiration was similar in all 3 groups

Discussion Increase in LF/HF at Tilt reflects an increase in sympathetic tone Initiation of OMT at Tilt resulted in change back to parasympathetic tone Shift from sympathetic to parasympathetic environment demonstrates OMT ability to overcome sympathetic tone

Discussion Lee et al 3 studied effect of head-down flexion on HRV Maneuver significantly affected autonomic balance as measured by LF/HF ratio Generally recognized that respiration has important effect on HRV 4 Our study showed respiration was not affected by body position or group Study results not influenced by alterations in respiration

Discussion Montano et al 5 observed comparable changes in heart rate and spectral analysis 60 degree head-up tilt LF nu increased in tilt position; HF nu decreased LF/HF ratio increased Primary difference in studies was OMT intervention in present study Application of OMT in Tilt eliminated 62% of increase in LF/HF seen in Control Tilt

Conclusions Quantitative relationship exists between OMT and sympathovagal balance Cervical myofascial release shifts sympathovagal balance from sympathetic to parasympathetic Establishes plausible mechanism for how OMT works in the body Support for using HRV as method to measure autonomic change

Future Studies Use of different OMT techniques Use of subjects with various chronic health conditions

References Kautzner J, Camm AJ. Clinical relevance of heart rate variability. Clin Cardiol Feb;20(2): Sztajzel J. Heart rate variability: a noninvasive electrocardiographic method to measure the autonomic nervous system. Swiss Med Wkly Sep 4;134(35- 36): Lee CM, Wood RH, Welsch MA. Influence of head-down and lateral decubitus neck flexion on heart rate variability. J Appl Physiol Jan;90(1): Hayano J, Mukai S, Sakakibara M, Okada A, Takata K, Fujinami T. Effects of respiratory interval on vagal modulation of heart rate. Am J Physiol Jul;267(1 Pt 2):H Montano N, Ruscone TG, Porta A, Lombardi F, Pagani M, Malliani A. Power spectrum analysis of heart rate variability to assess the changes in sympathovagal balance during graded orthostatic tilt. Circulation Oct;90(4):