Cambras, Trinitat, Castro-Marrero, Jesús, Zaragoza, Maria Cleofé et al. · PloS one · 2018 · DOI
This study compared daily activity patterns and skin temperature regulation in 10 women with ME/CFS and 10 healthy women over a week in both winter and summer. While sleep patterns were similar between groups, people with ME/CFS had lower overall daily activity levels and their bodies showed weaker responses to the normal daily rhythm patterns that healthy people display (like a post-lunch energy dip). The findings suggest that ME/CFS may involve problems with how the body's internal clock and temperature regulation systems work.
This research provides objective evidence that ME/CFS involves measurable disruptions in circadian regulation and autonomic function beyond subjective fatigue reports. Understanding these physiological abnormalities may help validate ME/CFS as a biological condition and potentially identify new targets for treatment. The findings strengthen the case for investigating hypothalamic dysfunction as a central mechanism in ME/CFS pathophysiology.
This study does not prove that circadian dysfunction causes ME/CFS symptoms—only that associations exist. The small sample size (10 per group) and female-only population limit generalizability to male patients or diverse populations. The study cannot determine whether these circadian abnormalities are a primary driver of ME/CFS or a secondary consequence of illness.
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 →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Cambras, Trinitat, Castro-Marrero, Jesús, Zaragoza, Maria Cleofé, Díez-Noguera, Antoni, & Alegre, José (2018). Circadian rhythm abnormalities and autonomic dysfunction in patients with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis.. PloS one. https://doi.org/10.1371/journal.pone.0198106
BibTeX
@article{mecfsatlas-cambras-2018-circadian-rhythm,
author = {Cambras, Trinitat and Castro-Marrero, Jesús and Zaragoza, Maria Cleofé and Díez-Noguera, Antoni and Alegre, José},
title = {Circadian rhythm abnormalities and autonomic dysfunction in patients with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis.},
journal = {PloS one},
year = {2018},
doi = {10.1371/journal.pone.0198106},
note = {PubMed: 29874259},
url = {https://www.mecfsatlas.com/evidence/cambras-2018-circadian-rhythm},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-29. https://www.mecfsatlas.com/evidence/cambras-2018-circadian-rhythm
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