Original ArticleEffects of Upper and Lower Cervical Spinal Manipulative Therapy on Blood Pressure and Heart Rate Variability in Volunteers and Patients With Neck Pain: A Randomized Controlled, Cross-Over, Preliminary Study
Introduction
Hemodynamic parameters (blood pressure [BP] and heart/pulse rate) have been studied pre and post cervical1, 2, 3, 4, 5 and thoracic manipulation.2, 6, 7, 8 Hemodynamic changes have also been reported following atlas SMT, although the results are somewhat controversial with no significant changes in BP1or decrease in BP.9, 10, 11The results of studies concerning SMT to treat hypertension have not been clinically concluded12, 13, 14 with the bias of hypotensive complication12 and decreased diastolic BP.13The possible underlying mechanisms of spinal manipulative therapy (SMT) and hemodynamic changes, such as autonomic regulation, the effects of the pressor reflex and anatomical abnormal positions, are still poorly understood.2, 3, 10, 11
Heart rate variability (HRV) analysis is a noninvasive and widely used technique15, 16, 17, 18, 19, 20, 21 which can provide important clinical information on the autonomic nervous system (ANS) and central nervous system because cyclical variation in heart rate is mediated by central neural mechanisms via baroreceptors and chemoreceptors.17 HRV is used mostly to predict heart conditions, such as myocardial infarction22 and to hypothesize the underlying mechanism of anesthetic drugs on hemodynamic changes.20, 21
The sympathetic and parasympathetic components of HRV are active over different frequency ranges. The low-frequency component (LF, 0.05– 0.15 Hz) is influenced by both cardiac sympathetic and parasympathetic activity16 and the high-frequency component (HF, > 0.15 Hz) originates from cardiac parasympathetic activity.18 Therefore, the LF/HF ratio reflects dominance of cardiac sympathetic activity.19, 20
Clinical information on the effect of SMT on the ANS and central nervous system using HRV analysis is sparse. HRV analysis showing cardiac autonomic functions has been conducted following spinal manipulation in the cervical2, 5 and thoracic regions.2, 6 As well, HRV analysis was examined in pain-free patients vs patients with lower back pain who received one chiropractic treatment at L5.23 However, information on hemodynamic parameters and HRV analysis is still lacking in acute mechanical neck pain patients after receiving SMT in the upper (C1 and C2) and lower (C6 and C7) cervical regions.
In this study, two hypotheses were tested: 1) parasympathetic response would be predominant after SMT of an upper cervical segment (C1 and C2 vertebrae) and sympathetic response would be predominant after SMT of a lower cervical segment (C6 and C7) in painless healthy volunteers, and 2) this predominance of parasympathetic or sympathetic responses would be altered in acute mechanical neck pain patients after SMT. The aims of this study are therefore to investigate whether there is a relationship between SMT of the upper versus lower cervical spine and autonomic response in pain free subjects and acute mechanical neck pain patients.
Section snippets
Methods
This study was approved by the International Medical University's (IMU) Joint-Committee of the Research and Ethics Committee with IRB number; IMUJC 181110. Ten asymptomatic normotensive volunteers and ten normotensive patients presenting to an academic chiropractic clinic complaining of acute neck pain (American Society of Anesthesiologist physical status I and II) were recruited with written informed consent in this study. A computer based random number generator produced a list used to assign
Results
The demographic and anthropometric characteristics of the participants (gender, age, body weight and height) are shown in Table 1. The ages ranged from 19 to 23 years and from 18 to 23 years in the volunteer group and in the patient group respectively. Baseline HR and BP were comparable in the volunteer and patient groups (Table 2A, Table 2B), but a statistically significant difference (P = .002) in BP was observed after upper cervical SMT in the volunteer group (− 11 ± 6 mmHg) and patient group (−
Discussion
The results of this study demonstrate that parasympathetic response was predominant after SMT applied to an upper cervical segment with a significant decrease in systolic BP. As well, a sympathetic response was predominant after SMT of a lower cervical segment in the healthy volunteer group. However, there was decreased sympathetic action with parasympathetic predominance, which was associated with decreased systolic BP and NPS, following both upper and lower cervical SMT in the patient’s group.
Limitations
Limitations of the study include: The sample of patients was not large enough to discover clinically significant changes in HRV, blood pressure and pain measurements. Because of the small sample size, a type II error is possible. Future research should therefore involve a randomized clinical trial with a larger sample size. Another limitation is that no control or sham group was utilized in this study. There was also a lack of control over variables that could have affected cardiovascular
Conclusion
Our report provides early evidence that HRV analysis is a noninvasive method that applies to the assessment of changes in sympathovagal regulation associated with hemodynamic and NPS score changes. These preliminary findings suggest that upper cervical SMT may enhance dominance of parasympathetic and lower cervical SMT may enhance dominance of sympathetic activity in a young volunteer group. However, dominance of parasympathetic activity was found in patients with neck pain that received both
Funding Sources and Conflicts of Interest
This study was supported by research endorsement funds of the International Medical University. No conflicts of interest were reported for this study.
References (39)
- et al.
Immediate effects of atlas manipulation on cardiovascular physiology
Clin Chiropr
(2012) - et al.
Sympathetic and parasympathetic responses to specific diversified adjustment to chiropractic vertebral subluxations of the cervical and thoracic spine
J Chiropr Med
(2008) Significant changes in systolic blood pressure post vectored upper cervical adjustment vs resting control groups: a possible effect of the cervicosympathetic and/or pressor reflex
J Manipulative Physiol Ther
(2001)- et al.
Innocuous mechanical stimulation of the neck and alterations in heart-rate variability in healthy young adults
Auton Neurosci
(2001) - et al.
The effects of thoracic manipulation on heart rate variability: a controlled crossover trial
J Manipulative Physiol Ther
(2006) - et al.
Immediate effects of anterior upper thoracic spine manipulation on cardiovascular response
J Manipulative Physiol Ther
(2013) - et al.
Blood pressure changes in African American patients receiving chiropractic care in a teaching clinic: a preliminary study
J Chiropr Med
(2013) - et al.
Spinal manipulation to treat hypertension: a systematic qualitative literature review
J Manipulative Physiol Ther
(2012) - et al.
Time frequency spectral analysis of HR variability during induction of general anaesthesia
Br J Anaesth
(1997) - et al.
Heart rate variability modulation after manipulation in pain-free patients vs patients in pain
J Manipulative Physiol Ther
(2009)
Chiropractic manipulation affects the differences between arterial systolic blood pressures on the left and right in normotensive subjects
J Manipulative Physiol Ther
Short-term effects of manual therapy on heart rate variability, mood state, and pressure pain sensitivity in patients with chronic tension-type headache: a pilot study
J Manipulative Physiol Ther
Cervical mobilisation: concurrent effects on pain, sympathetic nervous system activity and motor activity
Man Ther
Effect of chiropractic care on heart rate variability and pain in a multisite clinical study
J Manipulative Physiol Ther
Heart rate variability modulation after manipulation in pain-free patients vs patients in pain? The importance of controlling for respiration rate changes
J Manipulative Physiol Ther
Preliminary study of blood pressure changes in normotensive subjects undergoing chiropractic care
J Manipulative Physiol Ther
Effects of chiropractic treatment on blood pressure and anxiety: a randomized, controlled trial
J Manipulative Physiol Ther
A single mechanical impulse to the neck: does it influence autonomic regulation of cardiovascular function?
Chiropr J Aust
Atlas vertebra realignment and achievement of arterial pressure goal in hypertensive patients: a pilot study
J Hum Hypertens
Cited by (33)
The effectiveness of an osteopathic manual technique compared with a breathing exercise on vagal tone as indicated by heart rate variability, a crossover study
2024, Journal of Bodywork and Movement TherapiesEffect of Seated Cervical Spinal Manipulation on Autonomic Nervous System Activity as Measured by Heart Rate Variability and Plasma Norepinephrine Levels: A randomized Pre- and Poststudy
2024, Journal of Manipulative and Physiological TherapeuticsApplication of high-velocity low-amplitude technique in cervicothoracic junction produces cardiovascular responses in subjects with C7-T1 dysfunction: Randomized crossover trial
2023, International Journal of Osteopathic MedicineConservative Treatment Using Chiropractic Care and Orofacial Myofunctional Therapy for Obstructive Sleep Apnea: A Case Report
2023, Journal of Chiropractic MedicineReview of effects of spinal manipulative therapy on neurological symptoms
2023, Journal of Bodywork and Movement TherapiesMitigating Bias in the Measurement of Heart Rate Variability in Physiological Studies of Spinal Manipulation: A Comparison Between Authentic and Sham Manipulation
2022, Journal of Manipulative and Physiological Therapeutics