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The Hidden Causesof Chronic Pain
Emerging Research

How Sustained Stress Rewrites Pain Thresholds

Threat states are not merely unpleasant. They change immune signalling, muscle guarding, and the efficiency of the body's own pain brakes.

Dr. Elena MarshPhD, Pain Neuroscience10 min read

In brief

  • Chronic threat states alter HPA-axis signalling and immune activity.
  • Stress-induced analgesia is short-term; sustained stress often reverses it.
  • Psychological safety appears to be a physiological variable, not a soft one.
  • Mechanistic evidence is stronger than intervention evidence here.

Evidence label: Emerging Research — Early but credible findings — small trials, mechanistic studies, or replication still in progress.

Acute stress and chronic stress do opposite things

Acute stress is analgesic. This is well documented and evolutionarily sensible: the animal escaping the predator should not be slowed by an injury. Sustained stress behaves differently. Prolonged activation is associated with dysregulated cortisol rhythms, elevated inflammatory markers, and reduced efficiency of descending inhibition.

The direction of the effect flips. The same system that protects you for an hour can sensitise you over a year.

Three plausible pathways

First, neuroimmune signalling: sustained stress promotes a pro-inflammatory state, and inflammatory mediators lower nociceptor thresholds. Second, motor: persistent guarding and altered breathing patterns change load distribution and reduce movement variability. Third, appraisal: under threat, ambiguous sensations are more likely to be interpreted as dangerous, and interpretation shapes output.

We label this article Emerging Research deliberately. The mechanisms are well supported in laboratory work; the clinical trials that would let us state effect sizes for stress-targeted treatment of chronic pain are smaller and less consistent.

  • Neuroimmune: inflammatory mediators lower nociceptor thresholds
  • Motor: guarding, breath-holding, reduced movement variability
  • Appraisal: threat context biases interpretation of sensation

Safety as a physiological input

Perceived safety is measurable in its downstream effects: heart-rate variability, muscle tone, pain thresholds. This is the strongest scientific justification for approaches that look, from the outside, like wellness — paced breathing, predictable routines, social connection, environments a person can control.

It is also where the field is most vulnerable to overclaiming. That a mechanism exists does not mean any given programme reliably moves it. Treat confident promises with suspicion, including ours.

The nervous system does not ask whether the threat is physical. It asks whether it is over.

Common questions

Does this mean my pain is caused by stress?
Rarely by stress alone. Stress is better understood as a modulator that raises or lowers sensitivity alongside other contributors.

References

  1. 1Hannibal KE, Bishop MD. Chronic stress, cortisol dysfunction, and pain: a psychoneuroendocrine rationale for stress management in pain rehabilitation. Physical Therapy, 2014
  2. 2Slavich GM, Irwin MR. From stress to inflammation and major depressive disorder: a social signal transduction theory of depression. Psychological Bulletin, 2014

Written by

EM

Dr. Elena Marsh

PhD, Pain Neuroscience

Elena researches nociplastic pain and threat learning. She writes about what the evidence supports, what it does not, and where the honest uncertainty lies.

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