van Campen, C Linda M C, Rowe, Peter C, Verheugt, Freek W A et al. · Physiological reports · 2023 · DOI
This study looked at how carbon dioxide (CO2) levels in the blood affect blood flow to the brain when people stand up or tilt on a table. Researchers compared 535 women with ME/CFS to 34 healthy women. They found that CO2 does affect brain blood flow in both groups similarly, but CO2 changes only partially explain why ME/CFS patients often have reduced blood flow to the brain during position changes.
ME/CFS patients commonly experience inadequate blood flow to the brain during position changes, which contributes to symptoms like dizziness and cognitive difficulties. Understanding whether CO2-related mechanisms explain this problem helps researchers identify the true cause and could guide targeted treatments. This study clarifies that CO2 regulation is not the primary culprit, pointing investigators toward other mechanisms.
This study does not prove what actually causes the abnormal brain blood flow in ME/CFS—only that CO2 changes are not the main explanation. It is a cross-sectional snapshot and cannot establish causation or long-term outcomes. The findings apply primarily to women and may not generalize to men with ME/CFS.
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
van Campen, C Linda M C, Rowe, Peter C, Verheugt, Freek W A, & Visser, Frans C (2023). Influence of end-tidal CO<sub>2</sub> on cerebral blood flow during orthostatic stress in controls and adults with myalgic encephalomyelitis/chronic fatigue syndrome.. Physiological reports. https://doi.org/10.14814/phy2.15639
BibTeX
@article{mecfsatlas-van-campen-2023-influence-end,
author = {van Campen, C Linda M C and Rowe, Peter C and Verheugt, Freek W A and Visser, Frans C},
title = {Influence of end-tidal CO<sub>2</sub> on cerebral blood flow during orthostatic stress in controls and adults with myalgic encephalomyelitis/chronic fatigue syndrome.},
journal = {Physiological reports},
year = {2023},
doi = {10.14814/phy2.15639},
note = {PubMed: 37688420},
url = {https://www.mecfsatlas.com/evidence/van-campen-2023-influence-end},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/van-campen-2023-influence-end
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