Objective: Several studies have reported the effects of various specific cervical chiropractic adjustments on blood pressure(1-5) and pulse rate.(1-3) However, those studies have been criticized due to small sample size and various methodological concerns. The purpose of this randomized controlled trial (RCT) was to measure the effects of specific cervical (C3 to Occiput [“C0”]) chiropractic adjustments on blood pressure (BP) and pulse rate (PR) in a larger sample size of both normotensive and hypertensive humans.

Methods: After IRB approval, Informed Consent was  obtained and 331 human subjects who met the inclusion  criteria were randomly assigned to one of three groups:  Control (N=108; no treatment, no placebo); Placebo Treatment (N=117; sham adjustment with inactive device); or Active Treatment (N=106; adjustment with active device). Subjects were seated in a relaxing climate-controlled room for a minimum of 15 minutes prior to obtaining a baseline blood pressure (BP) (systolic and diastolic) and pulse rate (PR) measurement with an electronic oscillometric BP monitor. The subjects were then moved to chairs stationed according to the study group in which they were assigned. Subjects had another BP and PR measured (“anxiety” BP and PR measurements) after being called upon for active treatment, placebo treatment, or no treatment at all. Active treatment involved the use of the Activator IV(6) adjusting instrument to correct subluxations detected according to the Activator Methods Chiropractic Technique for cervical vertebrae C3 to C0. Placebo treatment was performed with an Activator II8 adjusting instrument in the “off” position which mimics all aspects of the treatment that is administered when in the “on” position but no manipulative force is delivered. Following active treatment (or placebo treatment or no treatment), subjects had their BP and PR measured once again.

Results: Subjects ranged in age from 18 to 85 years old (mean age = 52) and 64% of them were female. Systolic and diastolic BP decreased significantly (p<0.0001) in the active treatment group, whereas no significant changes occurred in the placebo treatment and control groups. Similarly, PR decreased significantly (p<0.0001) in the active treatment group, whereas no significant changes occurred in the placebo treatment and control groups.

Discussion: Similar smaller studies, utilizing various chiropractic adjusting techniques, served as the foundation for this larger and important RCT. The results of this RCT indicate, with strong statistical significance, that specific cervical (C3 to C0) chiropractic adjustments decrease systolic and diastolic BP, as well as PR.

Conclusion: This significant and important RCT demonstrates that specific cervical chiropractic adjustments decrease BP and PR. In follow-up to this RCT, a longitudinal pilot study of both normotensive and hypertensive subjects is currently in progress by the authors to determine how long a decrease in BP and PR is sustained following specific cervical chiropractic adjustments. Given the worldwide burden of hypertension and its adverse effects on health, further studies on the effects of chiropractic adjustments on BP and PR are warranted.

Fourth Place Research Prize at the 11th WFC Biennial Congress in Rio de Janiero, Brazil.

Author information: Steven Roffers, Laura Huber, David Morris, Anquonette Stiles, Derek Barton, Therese House