What Neurophysiology Is Discovering About Stress
For most of modern medicine’s history, the spine has been viewed primarily as a structural system—bones, discs, ligaments, and joints. Chiropractic, however, has long emphasized a different perspective: that spinal mechanics influence the nervous system, which in turn regulates many processes throughout the body
In recent decades, advances in neurophysiology and heart rate variability (HRV) measurement have allowed researchers to examine this question more closely.
While the science is still evolving, several studies suggest that spinal adjustments may influence autonomic nervous system function, which is closely tied to stress regulation.
This doesn’t mean chiropractic care is a universal solution. But the research does raise an interesting possibility: for some individuals, improving spinal function may help the nervous system operate in a more balanced state.
Below are three influential studies often discussed in chiropractic neurophysiology research.
1. The New Zealand Neurophysiology Studies on Spinal Manipulation
Research led by Heidi Haavik, a neuroscientist at the New Zealand College of Chiropractic, has been widely cited in discussions of chiropractic and brain function.
Her work examined how spinal adjustments affect sensorimotor integration—the brain’s ability to process information from the body and coordinate responses.
One study used somatosensory evoked potentials (SEPs) to measure how the brain processes signals from the spine before and after adjustments.
Findings
- Significant changes occurred in the prefrontal cortex, the region associated with attention, decision-making, and autonomic regulation.
- The results suggested spinal adjustments may alter the way the brain integrates sensory information from the body.
Reference
Haavik H, Murphy B. Altered cortical processing of somatosensory input following chiropractic spinal manipulation. Journal of Manipulative and Physiological Therapeutics. 2007. Indexed in the National Library of Medicine (PubMed).
2. Spinal Adjustments and Heart Rate Variability
Heart rate variability (HRV) has become one of the most widely used physiological markers of autonomic nervous system balance.
Higher HRV is generally associated with:
- Greater parasympathetic (vagal) activity
- Lower physiological stress
- Better resilience to environmental demands
A multicenter clinical study measured HRV before and after chiropractic care.
Results
- Heart rate decreased following adjustments.
- Overall HRV increased.
- Parasympathetic activity increased relative to sympathetic activity.
These findings suggest chiropractic care may influence autonomic regulation, potentially shifting the body away from a constant “fight-or-flight” state.
Reference
Zhang J, et al. Effect of chiropractic care on heart rate variability and pain in a multisite clinical study. Journal of Manipulative and Physiological Therapeutics. 2006. Indexed in the National Library of Medicine.
Another study examined how spinal adjustments affect brain plasticity—the nervous system’s ability to adapt and reorganize.
Researchers measured motor control and cortical excitability using transcranial magnetic stimulation before and after chiropractic adjustments.
Findings
- Adjustments altered activity in areas of the brain responsible for movement control.
- The changes suggested improved communication between the spine and the brain.
Reference
Lelic D, et al. The effects of spinal manipulation on cortical drive to upper limb muscles. Brain Sciences. 2016. Indexed in the National Library of Medicine.
Stress, the Autonomic Nervous System, and Why HRV Matters
The autonomic nervous system has two major branches:
Sympathetic
- Fight-or-flight
- Stress response
Parasympathetic
- Rest and recovery
- Digestion, healing, regeneration
Chronic stress tends to push the body toward sympathetic dominance.
Many clinicians view HRV as a practical window into this balance. When HRV improves, it often reflects greater adaptability in the nervous system.
The research above suggests spinal adjustments may influence this system in measurable ways.
A Note on Pregnancy
Some chiropractors have also observed that maintaining pelvic and spinal alignment during pregnancy may help create a more balanced environment for both mother and baby.
A few clinical reports suggest that chiropractic care during pregnancy may be associated with:
- Reduced back and pelvic pain
- Improved comfort during the third trimester
- Potentially shorter labor times and easier gestation for some women
One retrospective study examining chiropractic care during pregnancy reported shorter labor durations among women receiving regular adjustments compared with population averages.
Reference
Fallon J. Chiropractic care and pregnancy outcomes. Journal of Manipulative and Physiological Therapeutics. 1991.
It’s important to note that these findings are observational, and more controlled studies are needed. Still, many midwives and obstetric practitioners refer patients for chiropractic care to help maintain pelvic biomechanics during pregnancy.
A Reasonable Perspective
The evidence does not suggest chiropractic care is a cure-all. But it does indicate that spinal adjustments may have measurable effects on nervous system function.
For some individuals—particularly those dealing with chronic stress, musculoskeletal dysfunction, or autonomic imbalance—chiropractic care may be a useful component of a broader health strategy.
The nervous system regulates nearly every system in the body. Anything that helps it function more efficiently is worth studying carefully.
And in that sense, the emerging research into spinal adjustments and neurophysiology is less about ideology and more about curiosity: understanding how structure, movement, and the nervous system interact.
There is still much to learn, but the direction of the research is becoming increasingly interesting.
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Header image: Neurology