E3 PreliminaryModerate confidencePEM unclearReview-NarrativePeer-reviewedReviewed
Mechanisms Explaining Muscle Fatigue and Muscle Pain in Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): a Review of Recent Findings.
Gerwyn, Morris, Maes, Michael · Current rheumatology reports · 2017 · DOI
Quick Summary
This review examines why ME/CFS patients experience muscle fatigue and pain. Researchers found that several biological problems may contribute to these symptoms: damaged cellular energy factories (mitochondria), harmful stress molecules building up in the body, and reduced production of protective proteins. These problems together may explain why ME/CFS patients get tired quickly and struggle with exercise.
Why It Matters
Understanding the biological causes of muscle dysfunction could help develop targeted treatments for ME/CFS patients. By identifying multiple interconnected mechanisms rather than a single cause, this work supports more comprehensive approaches to symptom management and points researchers toward specific pathways worth investigating further.
Observed Findings
- Chronic oxidative and nitrosative stress documented in multiple ME/CFS patient populations
- Mitochondrial dysfunction detected in patient muscle tissue
- Reduced heat shock protein production in affected individuals
- Elevated low-grade inflammation markers in many patients
- Objective evidence of increased muscle fatigue and impaired muscle contractility during or after exercise
Inferred Conclusions
- Chronic O&NS, low-grade inflammation, and impaired heat shock protein production likely work together to explain exercise intolerance in ME/CFS
- These biological abnormalities appear to impair both muscle repair after exercise and the normal adaptive responses to physical activity
- Multiple interconnected mechanisms rather than a single cause may underlie ME/CFS muscle dysfunction
Remaining Questions
- Do these mechanisms occur in all ME/CFS patients, or only a subset? If subset-specific, what distinguishes affected patients?
- Which of these abnormalities is primary, and in what sequence do they develop?
- What triggers the initial activation of chronic oxidative stress and inflammation in ME/CFS?
What This Study Does Not Prove
This review does not establish that O&NS, mitochondrial impairment, or heat shock protein reduction directly cause muscle symptoms in all ME/CFS patients—it identifies associations and proposed mechanisms based on existing literature. It does not determine which mechanism is primary or whether these abnormalities are cause, consequence, or both. The review also cannot rule out other contributing biological factors not discussed.
Tags
Symptom:Post-Exertional MalaisePainFatigue
Biomarker:MetabolomicsBlood Biomarker
Method Flag:PEM Not DefinedWeak Case Definition
Metadata
- DOI
- 10.1007/s11926-017-0628-x
- PMID
- 28116577
- Review status
- Editor reviewed
- Evidence level
- Early hypothesis, preprint, editorial, or weak support
- 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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