Fibromyalgia and the Fight-or-Flight Response

You wake up already braced. The pain is there before the day begins. A stressful week makes it worse. A calm week does not always make it better. Your labs come back normal, which only deepens the confusion.

There is a reason for this pattern. It involves a system built to protect you: the fight-or-flight response.

The search for damage keeps coming up empty

Most fibromyalgia care looks for something broken. Scans, bloodwork, a structural cause. When the tests come back clean, you are often sent home without an answer. But no visible damage does not mean no cause. Modern pain science points somewhere else: the nervous system itself.

Fight-or-flight, stuck on

Fight-or-flight is your sympathetic nervous system. It evolved for short bursts of danger. Heart rate up, muscles tense, senses sharp, attention locked on threat. That state is useful for minutes. It is costly over months.

In fibromyalgia, this system tends to stay switched on. Researchers have described persistent, exaggerated sympathetic activity in people with fibromyalgia, paired with a blunted response to new stressors. A body running in chronic threat behaves differently. Sleep frays. Digestion stalls. Muscles stay guarded. Pain climbs.

Why the volume gets turned up

When the nervous system stays activated, the brain and spinal cord amplify incoming signals. This is called central sensitization, and it is the best-supported model of fibromyalgia. The pain is real. It is also amplified. An ordinary touch can register as pain because the system is set to maximum gain.

The part that changes everything

This pattern is learned and dynamic, not fixed damage. That means it can be unlearned. In a randomized trial of a method that retrains how the brain interprets pain, two thirds of chronic pain patients were pain-free or nearly pain-free afterward, compared with one in five on placebo. The gains largely held a year later.

Your body is not broken. Your nervous system is being protective. The work is to teach it, slowly and credibly, that it is safe.

One thing to try today

Downshift the system on purpose. For two minutes, breathe so your exhale is longer than your inhale. A four-count in, a six or eight-count out. A long exhale is one of the few direct levers you have on the sympathetic nervous system. It will not erase pain. It begins to signal safety.

References

1. Ashar YK, Gordon A, Schubiner H, et al. Effect of Pain Reprocessing Therapy vs Placebo and Usual Care for Patients With Chronic Back Pain: A Randomized Clinical Trial. JAMA Psychiatry. 2022;79(1):13-23.
2. Clauw DJ. Fibromyalgia: A Clinical Review. JAMA. 2014;311(15):1547-1555.
3. Martinez-Lavin M. Fibromyalgia: When Distress Becomes (Un)sympathetic Pain. Pain Research and Treatment. 2012.

This article is educational and is not medical advice.