Ramakers, Indra, Van Den Houte, Maaike, Van Oudenhove, Lukas et al. · Applied psychophysiology and biofeedback · 2023 · DOI
This study looked at how people with ME/CFS, fibromyalgia, burnout, and panic disorder breathe differently compared to healthy people. Researchers measured carbon dioxide levels in participants' breath while they rested and during a breathing challenge. They found that people with chronic conditions like ME/CFS showed less active stress responses in their breathing, while those with acute stress conditions showed overactive breathing patterns.
This study provides objective physiological evidence that ME/CFS involves distinct respiratory regulation patterns that differ from acute stress disorders, potentially supporting a biological mechanism underlying ME/CFS symptoms. Understanding these differences helps distinguish ME/CFS from panic disorder and stress-related conditions, which is clinically important since patients are sometimes incorrectly diagnosed with anxiety disorders.
This study does not prove that abnormal CO₂ regulation causes ME/CFS symptoms or is the primary mechanism of disease—it only shows an association. The cross-sectional design cannot establish causality, temporal relationships, or whether respiratory dysregulation is a cause or consequence of the condition. It also does not establish whether this pattern would be useful for diagnosis or treatment.
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
Ramakers, Indra, Van Den Houte, Maaike, Van Oudenhove, Lukas, Van den Bergh, Omer, & Bogaerts, Katleen (2023). End-Tidal CO<sub>2</sub> in Patients with Panic Disorder, Stress-Related or Functional Syndromes, Versus Healthy Controls.. Applied psychophysiology and biofeedback. https://doi.org/10.1007/s10484-022-09573-z
BibTeX
@article{mecfsatlas-ramakers-2023-end-tidal,
author = {Ramakers, Indra and Van Den Houte, Maaike and Van Oudenhove, Lukas and Van den Bergh, Omer and Bogaerts, Katleen},
title = {End-Tidal CO<sub>2</sub> in Patients with Panic Disorder, Stress-Related or Functional Syndromes, Versus Healthy Controls.},
journal = {Applied psychophysiology and biofeedback},
year = {2023},
doi = {10.1007/s10484-022-09573-z},
note = {PubMed: 36481961},
url = {https://www.mecfsatlas.com/evidence/ramakers-2023-end-tidal},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-25. https://www.mecfsatlas.com/evidence/ramakers-2023-end-tidal
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