Author: Shana L Johnson MD, AskDrShana



Nerves gone rogue! How stress sparks extreme pain


Imagine suffering from constant headaches, debilitating back pain, or embarrasing digestive symptoms but being told nothing is wrong. Your told your medical tests are mostly normal. This discrepancy between pain and pathology can be explained by nerve sensitization. This is a process where an issue with the body shifts from the injury area, like the back, to the nervous system. When this happens, a different treatment approach is needed. This shift in pathology is often missed.

Chronic headaches, back pain, and irritable bowel belong to a group of disorders called central sensitization syndromes (CSS). They all share the feature of nerve sensitization, which makes the nerves more sensitive to stimuli. Sensitization makes people feel more pain, more often. Stress is a risk factor for developing these conditions and can spark this dysfunction in the nervous system. CSS treatment will be covered in-depth in the upcoming book, Sunbreak (available on Amazon, summer 2023).


Listed below are common CSS.


Body SystemSensitization syndrome
Joints/muscleschronic back pain and neck pain
chronic muscle pain (myofascial pain syndrome)
Digestivechronic heartburn, stomach pain
irritable bowel syndrome
Neurologicmigraine headaches
tension-type headaches
Urinarychronic bladder pain (i.e. interstitial cystitis)


By some estimates, CSS are the most common reason for patient visits to an outpatient clinic. An estimate of upwards of 30 million adults in the United States suffers from one or more sensitization syndromes (Yunus MB. Current Rheumatology Reviews, 2015, 11, 70-85). They are a common reason for chronic pain. And a far-too-common reason people seek out opioids.


Why does this happen?

Nerve sensitization arises from dysfunction in the nervous system. Abnormalities develop in how pain signals are transmitted, processed, and perceived. Think of the brain and nerves like an electrical grid. The grid maintains balance in the system, adjusting its inputs and outputs, creating balanced flow of signals throughout the body. Nerve sensitization is like a malfunctioning electrical grid. The signal frequency is turned up too high, disrupting the function of the entire system. This malfunction results in the amplification of incoming pain signals and the loss of pain signal inhibition. Loss of two critical processes results in more pain and less protection.


Sensitization causes hypersensitivity

Sensitization intensifies pain. There is excessive sensitivity to sensory inputs such as touch, pressure, and movement. For example, let’s look at two people, one with and the other without sensitization. They both lift a 100-pound box and feel a pull in the back. They both experience the same amount of injury. The person without sensitization reports the pain as a “3 out of 10.” Meanwhile, the person with sensitization reports the pain as a “7 out of 10.” The nerves are telling the brain it hurts more than what a person without the condition feels.


Sensitization causes more than pain symptoms

Sensitization syndromes cause system-wide symptoms. The non-pain symptoms are just as problematic as the pain! They include fatigue, concentration difficulties, disrupted sleep, and sensitivity to light, sound, and smells. 

The fatigue is severe with a much lower energy level compared to others of the same age and health. Additionally, fatigue sets in sooner and lasts longer. For example, after an hour of intense exercise, someone with sensitization may need to rest for the remainder of the day.

Cognitive changes are a common complaint. The changes are often described as brain fog. It is hard focus for a long time and thinking feels slowed. Memory is not as sharp. 

Another non-pain symptom from sensitization is poor sleep. Sleep issues range from frequent awakenings at night to unrefreshed sleep. To make matters worse, poor sleep increases pain sensitivity and worsens cognitive difficulties and fatigue independently of sensitization.

Some people also report sensitivity to light, sound, and smells. Certain smells, such as perfumes, may bring on feeling dizzy or nauseous. Flickering lights and loud noises trigger headaches and dizziness. 


Bottom line

With a sensitization disorder, you have the discomfort from the primary pain site (headaches, back pain, etc) and the non-pain symptoms. The non-pain symptoms include fatigue, brain fog, and poor sleep. Sensitization syndromes cause a massive amount of misery. CSS treatment will be covered in-depth in the upcoming Sunbreak book.