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The Science and Physiology behind the Chiropractic Adjustment, and how it affects Stress

Written by Tom Greenfield

Chiropractic is the science and art concerned with the relationship between the spinal column, synovial joints, and the nervous system, and how their function affects the restoration of health, primarily using the hands to adjust altered joint mechanics.

Research suggests that "Proper motion and alignment of the spinal synovial joints is a genetic requirement for health and a lack of proper motion in the spine represents a stressor",[1]. Therefore, we can deduce that any lack of movement actually leads to initiating a stress response in the body.

What is involved in a stress response?

1. Stressor events (real or imagined).

2. Cognitive appraisal and affective integration.

3. Neurological triggering mechanisms (locus coeruleus, limbic nuclei, hypothalamic nuclei).

4. The stress response (a physiological mechanism of mediation).

5. Target-organ activation.

6. Coping behaviour.

The brain is constantly taking in information through the neocortex, the amygdala in the limbic system, and the reticular formation [2]. This information is happening subconsciously and happens without comprehension, processed from vision, auditory, memory, smell, touch, and is complicated by emotions. Touch sensations can include pain fibres going up to the brain via the spinal cord, whereas the other stimuli happen directly into the neocortex of the brain. The brain then interprets this information and triggers the hypothalamus into a stress response. This trigger will kickstart the Autonomic nervous system by altering the levels of sympathetic and parasympathetic outflow. This outflow affects certain physiology and processes in the body, (see below).




To Muscles

Digestive System

Heart Rate


Resting State

Blood Pressure


Resting State

Immune Response






Inflammatory Response



From the above diagrams, we can see all of the organs that are affected in the stress response, which are all potentially triggered by a lack of movement in the spinal synovial joints. This is the key link to explaining how a lack of spinal movement can affect organ function.


Persistent activation of the stress response can cause changes to homeostatic mechanisms. The study of stress neurophysiology, in the evaluation of the manifestation of disease in the body, suggests that these chronic changes have detrimental effects on sub cortical structures. Furthermore, there is much scientific support for the notion that chronic activation of supraspinal systems will lead to maladaptation of homeostatic mechanisms, causing the impairment of processes within the body, and ultimately leading to visceral disorders, [4]. This will lead to medical diagnoses such as IBS, bloating, high blood pressure, high production of cholesterol, high blood glucose levels, and ultimately chronic fatigue, tiredness, sleep problems and depression of the thyroid.


It has been proposed that spinal manipulation of the thoracic spine has a direct effect on the ANS response [3]. This paper concluded that “thoracic Spinal manipulation has the potential to be used as a viable treatment option in a multitude of clinical problems characterised by ANS and HPA axis dysfunctions”.

A 2017 meta-analysis found that spinal manipulation can increase substance-p, neurotensin, oxytocin and interleukin levels and may influence cortisol levels post-intervention [5], further indicating that chiropractic can reduce the stress response markers.


It is suggested in the research that improper spinal movement causes stress on the brain. This can lead to a stress response and directly affect your organ function. The research also suggests that spinal manipulation can decrease the stress response, further cementing the view that proper spinal motion is a prerequisite for health.

1. J Biomech Eng. 2011 Jul; 133(7): 71010–NaN, Published online 2011 Aug 2. doi: 10.1115/1.4004493

2. G.S. Everly and J.M. Lating, A Clinical Guide to the Treatment 17 of the Human Stress Response, DOI 10.1007/978-1-4614-5538-7_2, © Springer Science+Business Media New York 2013, Available at

3. Kovanur Sampath K et al. Measureable changes in the neuro-endocrinal mechanism following spinal manipulation. Med Hypotheses (2015),

4. The organisation of the stress response, and its relevance to chiropractors: a commentary, Katie Hardy & Henry Pollard, Chiropractic & Osteopathy volume 14, Article number: 25 (2006), Available at

5. Kovanur et al (2017), Changes in biochemical markers following spinal manipulation-a systematic review and meta-analysis, Musculoskeletal Science and Practice, Volume 29, June 2017, Pages 120-131

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