Farquhar, William B, Hunt, Brian E, Taylor, J Andrew et al. · American journal of physiology. Heart and circulatory physiology · 2002 · DOI
This study looked at whether people with ME/CFS have lower blood volume (the amount of fluid circulating in their bodies) and whether this might explain their exercise problems. Researchers compared 17 ME/CFS patients with 17 healthy controls, measuring blood volume and fitness capacity. They found that ME/CFS patients had significantly reduced exercise capacity and a trend toward lower blood volume, and these two measurements were strongly related to each other.
Understanding the physiological mechanisms underlying exercise intolerance in ME/CFS is crucial for developing targeted treatments. This study provides evidence that impaired cardiovascular parameters, particularly blood volume, may be measurable contributors to reduced exercise capacity, potentially opening avenues for hemodynamic-focused interventions. The findings help shift understanding of ME/CFS from purely psychological causes to documented physiological abnormalities.
This study does not prove that low blood volume causes exercise intolerance; it only shows they are correlated. The cross-sectional design cannot establish causal relationships or determine whether low blood volume precedes reduced fitness or vice versa. The trend toward lower blood volume was not statistically significant (p=0.084), so the clinical relevance of this finding requires confirmation in larger studies.
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
Farquhar, William B, Hunt, Brian E, Taylor, J Andrew, Darling, Stephen E, & Freeman, Roy (2002). Blood volume and its relation to peak O(2) consumption and physical activity in patients with chronic fatigue.. American journal of physiology. Heart and circulatory physiology. https://doi.org/10.1152/ajpheart.2002.282.1.H66
BibTeX
@article{mecfsatlas-farquhar-2002-blood-volume,
author = {Farquhar, William B and Hunt, Brian E and Taylor, J Andrew and Darling, Stephen E and Freeman, Roy},
title = {Blood volume and its relation to peak O(2) consumption and physical activity in patients with chronic fatigue.},
journal = {American journal of physiology. Heart and circulatory physiology},
year = {2002},
doi = {10.1152/ajpheart.2002.282.1.H66},
note = {PubMed: 11748048},
url = {https://www.mecfsatlas.com/evidence/farquhar-2002-blood-volume},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-29. https://www.mecfsatlas.com/evidence/farquhar-2002-blood-volume
Contribute
Private, reviewed by a human. Not a public comment thread.