Exploring the Effects of Osteopathic Manipulative Treatment on Autonomic Function Through the Lens of Heart Rate Variability

Abstract

The osteopathic community has long hypothesized that the autonomic nervous system (ANS) represents one of the putative substrates through which osteopathic manipulative treatment (OMT) can improve body functions that have been altered by musculoskeletal alterations. Heart rate variability (HRV) is an important physiological measure of cardiac ANS activity. Emerging evidence suggests that OMT is associated with HRV changes that (i) are indicative of a larger cardiac vagal modulation, (ii) are independent from the part of the body needing treatment, (iii) occur even in the absence of musculoskeletal alterations. Yet, many questions remain unanswered, the duration of these effects and the specificity of HRV responses to different OMT techniques being perhaps the most critical. Therefore, this paper discusses prospects for future applications of HRV for the study of the influence of OMT on ANS function. Moreover, based on existing studies and preliminary data on the effects of OMT on HRV in specific pathological (hypertension) and physiological (stress exposure and recovery from sport competition) conditions that are commonly associated with increased sympathetic and/or decreased vagal activity, we propose that HRV analysis could be exploited to evaluate the effectiveness of OMT as a preventive or complementary strategy in clinical and non-clinical conditions characterized by ANS imbalance.

Keywords: autonomic; fatigue status; heart rate variability; hypertension; osteopathy; stress.

FIGURE 1

Pilot study conducted on 10 men with a confirmed diagnosis of hypertension [age: 54 ± 2 years; body mass index = 25.8 ± 1.0 kg/m²; non-smokers; no other clinical conditions; under regular antihypertensive treatment with calcium channel blockers (n = 6) and ACE inhibitors (n = 4)]. Blood pressure (BP) and heart rate variability (HRV) measures were obtained prior to and 48 h after an osteopathic manipulative treatment (OMT) protocol, consisting of four sessions of OMT, once a week for 4 weeks. Systolic (A) and diastolic (B) BP were measured with an electronic sphygmomanometer (A&D Medical: Model UA-631 V). High-frequency (HF, C) and low frequency (LF) /HF (D) data of HRV were calculated from ECG signals recorded with a BT16Plus device (Francesco Marazza Hardware & Software). ECG recordings lasted for 10 min in a supine position on a motorized table and during passive head-up tilting at 70°. Inner numbers in (C,D) represent delta changes (i.e., tilt value—supine value). Values are expressed as mean ± SEM. *indicates a significant difference (paired t-test p < 0.05).