Polli, Andrea, Van Oosterwijck, Jessica, Meeus, Mira et al. · Scandinavian journal of pain · 2019 · DOI
This study explored whether exercise-triggered immune system changes in ME/CFS patients are connected to increased pain sensitivity. Researchers compared immune markers and pain thresholds in ME/CFS patients and healthy people before and after two different types of exercise. They found a link between changes in a immune protein called C4a and pain sensitivity in ME/CFS patients, but this connection was weak and only showed up in some measurements.
Understanding whether immune activation directly causes the pain and symptom worsening that ME/CFS patients experience after exercise could guide future treatment strategies targeting immune pathways. This mechanistic insight may help explain post-exertional malaise and inform exercise prescription guidelines for this population.
This study does not prove that C4a activation causes pain sensitivity changes—correlation does not establish causation. The weak associations, inconsistent findings across different pain measurement sites, and possibility that other unmeasured mechanisms explain the symptoms mean we cannot yet claim the complement system is the primary driver of post-exercise pain worsening in 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
Polli, Andrea, Van Oosterwijck, Jessica, Meeus, Mira, Lambrecht, Luc, Nijs, Jo, & Ickmans, Kelly (2019). Exercise-induce hyperalgesia, complement system and elastase activation in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome - a secondary analysis of experimental comparative studies.. Scandinavian journal of pain. https://doi.org/10.1515/sjpain-2018-0075
BibTeX
@article{mecfsatlas-polli-2019-exercise-induce,
author = {Polli, Andrea and Van Oosterwijck, Jessica and Meeus, Mira and Lambrecht, Luc and Nijs, Jo and Ickmans, Kelly},
title = {Exercise-induce hyperalgesia, complement system and elastase activation in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome - a secondary analysis of experimental comparative studies.},
journal = {Scandinavian journal of pain},
year = {2019},
doi = {10.1515/sjpain-2018-0075},
note = {PubMed: 30325737},
url = {https://www.mecfsatlas.com/evidence/polli-2019-exercise-induce},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/polli-2019-exercise-induce
Contribute
Private, reviewed by a human. Not a public comment thread.