Can a Chiropractic Adjustment Change Stress Systems?

​There is mounting evidence for the positive effect of chiropractic adjustments to shift your autonomic system which may help you manage stress and boost your mood.
 
Chiropractic care has been shown to have an impact on our autonomic nervous system comprising of both sympathetic and parasympathetic nervous systems.  These systems are vital for regulating normal function of our bodies including our stress response to external stimuli. Interestingly, parasympathetic stimulation is also considered an effective therapy for major depression as it releases various chemicals and hormones such as neurotrophins which are essential for anti-depressive therapies, as well as brain-derived neurotrophic factor and nerve growth factor.(1)
 
Many studies have explored chiropractic cranial and vertebral adjustments, and spinal manipulative therapy in relation to autonomic functions. The parasympathetic nervous system arises from the cell bodies of cranial nerves III, VII, IX, X, and XI in the brainstem and from the second, third, and fourth sacral segments of the spinal cord. The cell bodies of the sympathetic fibers are in the lateral horns of the spinal cord of segments T1 through L2.(2)
The parasympathetic nervous system is related to the upper cervical region, so a cervical manipulation or adjustment results in a parasympathetic response (lowering of heart beat, reduction of blood pressure, pupil constriction), whereas manual adjustment of spinal regions with significant sympathetic innervation, i.e. the upper thoracic and lumbar regions, produces a sympathetic response (heart beat stimulation, blood pressure increase, pupil dilation).(1)
Several studies have been done observing the change in the autonomic nervous system after an adjustment by measuring the heart rate variability (HRV) before and after manipulation showing a clear shift to parasympathetic predominance due to the change in HRV values post adjustment.(3)
In a different study, Diastolic pressure was observed (indicating a sympathetic response) which dropped significantly post-adjustment among those receiving cervical adjustments, accompanied by a moderate clinical effect (0.50). Pulse pressure increased significantly among those receiving cervical adjustments, accompanied by a large effect size (0.82), suggesting that cervical adjustments may result in parasympathetic responses, whereas thoracic adjustments result in sympathetic responses.(2)
More research is needed in this area- however these early findings are exciting! If you or you know anyone who is interested in this give us a call for a consult!
 
References
1.         Kiani AK, Maltese PE, Dautaj A, Paolacci S, Kurti D, Picotti PM, et al. Neurobiological basis of chiropractic manipulative treatment of the spine in the care of major depression. Acta Biomed. 2020;91(13-s):e2020006.
2.         Welch A, Boone R. Sympathetic and parasympathetic responses to specific diversified adjustments to chiropractic vertebral subluxations of the cervical and thoracic spine. Journal of chiropractic medicine. 2008;7(3):86-93.
3.         Roy RA, Boucher JP, Comtois AS. Heart rate variability modulation after manipulation in pain-free patients vs patients in pain. J Manipulative Physiol Ther. 2009;32(4):277-86.