E3 PreliminaryPreliminaryPEM not requiredMechanisticPeer-reviewedReviewed
Standard · 3 min
Protracted effects of chronic stress on serotonin-dependent thermoregulation.
Natarajan, Reka, Northrop, Nicole A, Yamamoto, Bryan K · Stress (Amsterdam, Netherlands) · 2015 · DOI
Quick Summary
When the body experiences prolonged stress, it can damage the system that controls body temperature through a chemical messenger in the brain called serotonin. This study found that stressed animals had trouble warming up when exposed to cold—the opposite of what healthy animals normally do—and this problem persisted even after stress ended. By blocking stress hormones during the stressful period, researchers could prevent these temperature control problems, suggesting stress-related damage to thermoregulation might be reversible.
Why It Matters
Temperature dysregulation is a core symptom in ME/CFS, and this study identifies a plausible neurobiological mechanism linking chronic stress to persistent thermoregulatory deficits via serotonergic dysfunction. The finding that blocking stress hormone production during the stress period could prevent temperature control problems suggests potential therapeutic windows and mechanisms worth investigating in human ME/CFS populations.
Observed Findings
Chronic stress-exposed rats showed significantly elevated basal body temperature at 13:00 h compared to unstressed controls.
Unstressed rats increased body temperature appropriately during cold exposure; stress-exposed rats showed hypothermia instead.
Chronic stress reduced serotonin transporter protein immunoreactivity in the medial preoptic area.
Metyrapone treatment during stress prevented the development of stress-induced thermoregulatory impairment.
Serotonin agonist injection into the medial preoptic area produced exaggerated heat responses in stressed animals.
Inferred Conclusions
Chronic unpredictable stress produces long-lasting alterations in temperature regulation through decreased serotonin neurotransmission in the hypothalamus.
Stress hormones (corticosterone) mediate the development of these thermoregulatory deficits.
The serotonergic system in the brain's temperature control center (mPOA) is fundamentally altered by chronic stress in ways that persist beyond the stress period.
These mechanisms may explain thermoregulatory abnormalities observed in chronic stress-related disorders including chronic fatigue syndrome.
Remaining Questions
Do these thermoregulatory changes reverse over time, or are they permanent after chronic stress exposure?
What This Study Does Not Prove
This study does not prove that stress causes ME/CFS or that serotonin dysfunction is the sole cause of temperature problems in ME/CFS patients. The findings are from animal models and do not directly demonstrate the same mechanisms operate in humans. Additionally, the study does not establish whether these thermoregulatory changes are permanent or whether they could be reversed after stress exposure ends.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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