Hodges, L D, Nielsen, T, Baken, D · Clinical physiology and functional imaging · 2018 · DOI
This study compared how the bodies of people with ME/CFS, people with multiple sclerosis, and healthy people responded to exercise on two days in a row. Researchers found that people with ME/CFS got noticeably weaker on the second day of exercise, using less power while their bodies worked harder (higher oxygen use), which is different from how healthy people responded. This suggests that repeated exercise affects ME/CFS and MS differently, and these exercise tests might help doctors tell these conditions apart.
This study provides objective physiological evidence that ME/CFS produces abnormal exercise responses distinct from other fatigue-causing conditions like MS, which could help establish more rigorous diagnostic criteria. For patients, demonstrating that the body's response to repeated exercise is measurably different in ME/CFS validates the condition's biological basis and supports the reality of post-exertional malaise. This type of standardized testing may eventually assist clinicians in accurate diagnosis and help justify activity restrictions.
This pilot study does not prove that repeated exercise testing can be used clinically to diagnose ME/CFS, as the sample is very small and findings need replication in larger cohorts. It does not establish what causes the abnormal physiological response or whether it reflects underlying mitochondrial dysfunction, autonomic dysfunction, or other mechanisms. The study does not prove that post-exertional malaise is present, as symptom data are not reported—only physiological measurements.
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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