“Several studies in asymptomatic subjects have shown that adjustment techniques induce changes in physiological reflexes, increase neuromuscular excitability, and modify sensitivity.”

“The aim of this study was to evaluate the effects of cervical and thoracic adjustments on the plasmatic concentration of biochemical markers (neurotensin, orexin A, oxytocin, and cortisol). This study represents a preliminary step in advancing the understanding of the underlying mechanisms of adjustments and their effects.”

 “Taken together, the results of this study show that cervical and thoracic adjustments resulted in an increase in neurotensin, oxytocin, and plasmatic cortisol concentration in asymptomatic individuals. These neuropeptides are related to the modulation of nociception and stress-induced analgesia. These findings suggest that descending inhibitory pathway mechanisms may be involved in the physiological effects that follow adjustments.”


Key Concepts: Chiropractic adjustments, via their effects on the nerve pathways between the spine and the brain, stimulate the areas of the brain for sensori-motor integration and motor control/ strength/  coordination. However, chiropractic adjustments also stimulate the areas of the brain that regulate the release of pain modulating hormones/neuropeptides. “Several studies currently support the idea that the analgesic effect of manual therapy is mediated by central mechanisms of pain modulation through the modulation of neuropeptide production.”  


Plaza-Manzano, G. et al. (2014) Changes in Biochemical Markers of Pain Perception and Stress Response After Spinal Manipulation. Journal of Orthopaedic and Sports Physical Therapy 44(4); 231-239