News - Chiropractic
Chiropractic and the whole body response pt. 3/3
September, 2009
Prepared by: Shane J. Lynch, D.C.
Welch A, Boone R. Sympathetic and parasympathetic responses to specific diversified adjustments to chiropractic vertebral subluxtions of the cervical and thoracic spine. J Chiro Med 2008; 7: 86-93.
Sympathetic response=sympathetic nervous system (SNS); this system when activated causes an increase in heart rate, blood pressure, dilation of pupils, and decrease in gastrointestinal activity, to name a few. The sympathetic nervous system is also referred to as the “flight of fight” system.
Parasympathetic response=just the opposite of above; it is responsive during rest and relaxation.
Diversified adjustments=a chiropractic adjustment technique.
Vertebral subluxations=small spinal misalignments that chiropractors adjust.
Cervical spine=top part of your spine (i.e. the neck).
Thoracic spine=middle part of spine from bottom of neck to below the shoulders.
This is a recent study that examined the effects that adjustments on the cervical and thoracic spine have on the sympathetic and parasympathetic nervous system. The chiropractic objective is to adjust vertebral subluxations to enhance the function of the nervous system to allow the body to function at a higher capacity. The sympathetic nervous system is composed of nerves located in the area of the thoracic spine and the parasympathetic nerves are located close to the top of the cervical spine and at the sacrum. As pointed out by the authors of this study, “it is hypothesized that a thoracic adjustment, because of its close relationship with the SNS nerves would elicit a sympathetic response and a cervical adjustment would elicit a parasympathetic response”.
Key points:
“Diastolic (blood) pressure dropped significantly post-adjustment among those receiving a cervical adjustment”.
“Pulse pressure increased significantly among those receiving cervical adjustments”.
Pulse pressure=systolic (blood) pressure –diastolic (blood) pressure. Blood pressure is recorded as systolic pressure/diastolic pressure; for example, 120 mmg (systolic pressure)/80 mmg (diastolic pressure).
An increase in pulse pressure in this study was a good thing because it represented a decrease in diastolic pressure, accounted for by “lessening of arterial constriction while increasing vasodilatation”.
“The data revealed a significant decrease in diastolic, but not systolic, pressure in those receiving cervical adjustments. This observation has clinical applications because diastolic pressure has been shown to be a predictor separating patients with isolated vs essential hypertension”.
“…the pulse pressure finding plays a significant role in that either excessively high or low pulse pressures, commonly linked to changes in diastolic pressure, are considered risk factors for heart disease and premature death”.
The authors point out that this is significant because in this study chiropractic adjustments were shown to affect diastolic pressure, meaning that those with excessively high pulse pressures may benefit with such treatments.
“When considering the balance between parasympathetic/sympathetic activity (LF/HF), it was evident that, in each patient, the pre-to post-adjustment decrease in LF/HF was due to either a larger increase in sympathetic activity or a lesser decrease in sympathetic activity when compared with parasympathetic activity.”
Such results occurred with chiropractic adjustments to the thoracic spine, which is where nerves composing the sympathetic nervous system reside.
“The observations of this study suggest that cervical adjustments could manifest a shift to parasympathetic dominance, whereas thoracic adjustments could manifest a shift to sympathetic dominance”.
Wrap up:
The results of this study support the notion that chiropractors affect the nervous system with adjusting vertebral subluxations. This is not only important for the acutely injured patient, but it also provides some evidence that getting your spine checked on a regular basis (i.e. maintenance/wellness care) can have positive effects on the body beyond just the musculoskeletal system.
