The Physiology of Living Better: Why Asymptomatic People Benefit From Chiropractic Care
Originally published: 2025-11-19
A Study Ahead of Its Time
Most chiropractors intuitively know that people do not need to be in pain to benefit from chiropractic care. They see it every day. They watch families under care function better, adapt better, and live better. Yet for decades, critics insisted there was no scientific evidence of benefit in people without symptoms.
Long before “wellness care” became a buzzword, the Hannon review published in the Journal of Vertebral Subluxation Research challenged that entrenched assumption head on. It assembled more than twenty studies documenting objectively measured changes in physiology, structure and function in people specifically described as healthy, normal or asymptomatic.
This paper captured exactly what makes McCoy Press journals unique. It showed that vertebral subluxation correction is not about chasing pain. It is about restoring function to the nervous system and therefore to the entire body.
Why This Review Still Matters
Many newer subscribers may never have seen this landmark paper. Yet its message is even more relevant today as the chiropractic profession faces increasing cultural, political and regulatory pressure to narrow its scope to musculoskeletal pain.
This review does the opposite. It expands the conversation. It reframes chiropractic as an essential part of human performance, adaptability, and physiology.
What the Review Found
The review documented significant changes across multiple body systems in asymptomatic individuals following chiropractic adjustments. These included:
Neuromuscular and Structural Function
• Increased range of motion
• Decreased muscle tone and asymmetry
• Improved strength and coordination
• Enhanced balance and athletic performance
Autonomic and Cardiovascular Function
• Shifts in heart rate variability toward increased parasympathetic activity
• Changes in blood pressure parameters
• Measurable effects on reflexes and pupillary response
Immune and Endocrine Function
• Increased neutrophil and monocyte activity
• Changes in cortisol
• Short term shifts in beta endorphins
Respiratory and Pulmonary Function
• Improved lung volumes and airway function
• Increases in FVC and FEV-1 in both normal and subnormal subjects
Neurocognitive Function
• Faster reaction times
• Improved processing speed
• Visual acuity changes
• Altered cortical activity patterns
These are not subjective opinions. These are objective, measurable outcomes.
Why It Was Revolutionary
The genius of this review was not only what it measured. It was who it measured. Healthy people. Normal people. People without symptoms.
This overturned the idea that chiropractic is a treatment for pain. Instead, it framed chiropractic as a way to support the physiology of living systems.
“People do not need to be in pain to benefit from chiropractic. Improved function is measurable even in healthy individuals.”
Connecting It to Today’s Research Agenda
McCoy Press continues this tradition by documenting the effects of vertebral subluxation correction on physiology, adaptation and human performance. The current body of literature on HRV, immune function, neurodevelopment, pregnancy outcomes, breastfeeding, sleep and autonomic regulation all stand on the shoulders of foundational reviews like this one.
Today we see deeper mechanistic understanding. Today we have stronger tools of measurement. Today we have more published evidence than ever before.
But the core message is unchanged. Correcting vertebral subluxation influences the physiology of life.
“Chiropractic care may benefit every function of the body because every function of the body is under the control of the nervous system.”
Why Subscribers Should Revisit It Now
For new readers of our journals, this review is a reminder of why these publications exist and why your subscriptions matter. It highlights the type of research the mainstream avoids and the type of inquiry the profession desperately needs.
For longtime subscribers, it is a chance to reconnect with the roots of objective physiologic measurement in chiropractic research.
“The absence of symptoms does not equal the presence of health. Chiropractic research has been showing this for decades.”
Read and Share the Full Review
This paper remains one of the clearest explanations of why chiropractic care is for everyone. It is as relevant today as the day it was published and is an essential resource for chiropractors who want to communicate the bigger story of subluxation correction.
