At the Happy Spine, we intuitively know that people do not need to be in pain to benefit from chiropractic care. We see it every day. We 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.
Why This Review Still Matters
Even though the Hannon review was published in 2004, 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 (less stiffness)
• 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 (boosting the immune system)
• 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. What this tells us is that you don’t have to have symptoms in order to benefit from NeuroSpinal Optimization. You don’t have to wait until there’s something “wrong”. Aging doesn’t have to follow the established playbook.
What would our healthcare system look like if we didn’t wait for a health crisis to occur, but instead taught people how to build better health for themselves?