E1 ReplicatedModerate confidencePEM ✓ObservationalPeer-reviewedReviewed
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Cerebral blood flow is reduced in ME/CFS during head-up tilt testing even in the absence of hypotension or tachycardia

C. M. C. van Campen, F. C. Visser, P. C. Rowe · Journal of Internal Medicine · 2020 · DOI

Quick Summary

In the largest study of its kind, 429 ME/CFS patients underwent head-up tilt testing with simultaneous cerebral blood flow monitoring. Nearly all ME/CFS patients showed significantly reduced cerebral blood flow when upright, even when blood pressure and heart rate were normal. The reduction correlated with symptom severity.

Why It Matters

This large study demonstrates that reduced brain blood flow in upright posture is nearly universal in ME/CFS — even without classic POTS criteria being met. It explains the cognitive symptoms and post-exertional worsening that many patients experience and suggests that hemodynamic support may be a treatment avenue.

What This Study Does Not Prove

This study cannot determine whether reduced cerebral blood flow is a cause of ME/CFS, a consequence, or simply a feature. Treatment implications require separate trial evidence.

Topics

Tags

Method Flag:PEM_DEFINEDIOM_CRITERIABIOLOGICALLY_RELEVANTCLINICAL_ENDPOINTWeak Case Definition
Symptom:Orthostatic IntoleranceFatigue
Biomarker:Neuroimaging

Metadata

DOI
10.1111/joim.13042
Case definition
IOM/SEID Criteria
Sample size
429 patients
Control group
Yes
Review status
Editor reviewed
Evidence level
Replicated human evidence from multiple independent studies
Last updated
7 April 2026