E2 ModerateModerate confidencePEM not requiredCase-ControlPeer-reviewedReviewed
Physiological cost of walking in those with chronic fatigue syndrome (CFS): a case-control study.
Paul, Lorna, Rafferty, Danny, Marshal, Rebecca · Disability and rehabilitation · 2009 · DOI
Quick Summary
This study compared how much energy people with ME/CFS use when walking compared to healthy people. Researchers found that people with ME/CFS walk more slowly and use more energy per unit of distance covered, meaning their bodies have to work harder to move the same distance as healthy people.
Why It Matters
This study provides objective physiological evidence that ME/CFS affects how efficiently the body uses energy during basic physical activity. Understanding that walking requires disproportionate energy expenditure in ME/CFS helps validate the experience of fatigue and provides measurable data supporting the biological basis of the condition.
Observed Findings
- CFS subjects walked at significantly slower preferred walking speeds (0.84 m/s) compared to controls (1.19 m/s)
- At preferred walking speed, CFS subjects had lower absolute oxygen uptake than controls (both gross and net)
- At matched walking velocities, CFS subjects demonstrated significantly greater net physiological cost of gait compared to controls
- The physiological demand for walking in CFS subjects was disproportionate to distance covered
Inferred Conclusions
- Walking is metabolically less efficient in people with ME/CFS compared to matched healthy controls
- The reduced walking speed chosen by CFS subjects may represent an adaptive strategy to minimize energy cost
- Abnormal gait biomechanics or physiological inefficiency underlies the elevated energy demands in ME/CFS
- The mechanisms driving this inefficiency require further investigation
Remaining Questions
- What physiological or biomechanical factors cause the inefficient gait in ME/CFS (muscle fiber composition, motor control, mitochondrial function, etc.)?
- Does the elevated physiological cost of walking correlate with post-exertional malaise or disease severity?
What This Study Does Not Prove
This study does not explain why people with ME/CFS have higher physiological costs of walking—only that they do. It does not establish causation for this energy inefficiency or identify whether it results from muscle abnormalities, neurological factors, mitochondrial dysfunction, or other mechanisms. The cross-sectional design cannot determine whether inefficient gait is a cause or consequence of ME/CFS.
Tags
Symptom:Post-Exertional MalaiseFatigue
Biomarker:Blood Biomarker
Method Flag:PEM Not DefinedWeak Case DefinitionSmall Sample
Metadata
- DOI
- 10.1080/09638280802652015
- PMID
- 19848558
- Review status
- Editor reviewed
- Evidence level
- Single-study or moderate support from human research
- Last updated
- 12 April 2026
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 →
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