Fibromyalgia – Chapters

Fibromyalgia — Day 3: Central Sensitization — What Happens Inside the Nervous System

To truly understand fibromyalgia, we must look inside the nervous system. The pain is not imagined. It is processed differently.

The key concept is central sensitization. This refers to increased responsiveness of neurons in the spinal cord and brain to stimulation.

The Spinal Cord — The First Amplifier

When sensory nerves detect pressure, temperature, or injury, they send signals through peripheral nerves into the spinal cord. In a healthy system, the spinal cord filters and regulates those signals before passing them to the brain.

In central sensitization, neurons in the dorsal horn of the spinal cord become more excitable. They fire more easily. They fire longer. They amplify.

This means:

Mild pressure may feel painful (allodynia)

Moderate pain may feel severe (hyperalgesia)

Signals that should be filtered out are transmitted upward

Wind-Up Phenomenon

Repeated stimulation can cause something called “wind-up.” Each signal slightly increases neuron responsiveness. Over time, the baseline sensitivity rises.

Imagine turning a volume knob up slightly each day. Eventually, even quiet sounds become overwhelming.

Neurotransmitter Changes

Research has shown that people with fibromyalgia often have increased levels of excitatory neurotransmitters like substance P and glutamate in spinal fluid.

At the same time, inhibitory pathways — which normally dampen pain signals — may be less effective.

The balance shifts toward amplification.

The Brain — Interpretation Center

The brain does not simply receive pain signals. It interprets them. Brain imaging studies show increased activity in pain-processing regions in fibromyalgia patients.

These areas include:

Insula

Anterior cingulate cortex

Somatosensory cortex

When these regions become hyper-responsive, the experience of pain intensifies.

Descending Inhibitory Pathways

Normally, the brain sends signals downward to dampen pain input. These descending inhibitory pathways act like brakes.

In fibromyalgia, these brakes may be weaker. The system has less ability to calm itself.

The Role of Sleep in Sensitization

Deep sleep plays a critical role in nervous system recalibration. When slow-wave sleep is disrupted, inhibitory pathways weaken further.

This is why poor sleep often directly worsens pain the next day.

Sleep architecture restoration will be a major pillar in recovery.

Autonomic Nervous System Interaction

Chronic sympathetic activation — the “fight or flight” mode — increases neural excitability. Stress hormones such as cortisol and adrenaline can heighten sensory processing.

This explains why emotional stress often worsens physical pain in fibromyalgia.

Neuroplasticity — The Hope Mechanism

The same plasticity that allows sensitization also allows recalibration. Neural pathways can weaken if stimulation patterns change.

Recovery focuses on:

Improving sleep depth

Reducing sympathetic dominance

Gradual movement exposure

Lowering overall stress load

Stabilizing metabolic patterns

Readers interested in metabolic stabilization can review integrated approaches at HealthGPT.co.il, where metabolic and nervous system health are treated together.

Why Understanding This Matters

If fibromyalgia were purely structural damage, the strategy would be different. But because it is amplification, recovery focuses on modulation.

The goal is not to chase invisible injuries. The goal is to reduce nervous system reactivity.

Today’s Step

Notice whether stress, sleep, or emotional load changes your pain intensity. This awareness builds the foundation for targeted stabilization.

Tomorrow we explore why fibromyalgia pain becomes widespread rather than localized.