Stussman, Barbara, Camarillo, Nathan, McCrossin, Gayle et al. · Frontiers in neurology · 2025 · DOI
This study looked at post-exertional malaise (PEM)—the symptom worsening that happens after activity—in people with Long COVID. Researchers asked patients about PEM symptoms and had some patients do an exercise test to see if PEM actually occurred. While 67% of patients reported having PEM symptoms, only 6% actually showed clear PEM after the exercise test. When PEM did occur in Long COVID, it was less severe than what the researchers saw in ME/CFS patients.
This study addresses a critical gap in understanding PEM—distinguishing between what patients report and what clinicians can objectively measure. For ME/CFS patients and researchers, it provides important comparative data showing phenotypic differences between Long COVID and ME/CFS PEM presentations, which may guide diagnosis and treatment strategies. The findings suggest exercise testing could help personalize clinical management.
This study does not prove that PEM is absent in Long COVID or that exercise is universally safe for these patients; the 5.9% observed PEM rate reflects this small cohort under controlled conditions and may not represent real-world activity patterns. The discrepancy between self-reported (67%) and objectively observed (5.9%) PEM does not establish that subjective reports are inaccurate—it may indicate that standardized CPET does not adequately provoke individual PEM triggers. The study cannot establish causation or mechanistic explanations for PEM differences between conditions.
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
Stussman, Barbara, Camarillo, Nathan, McCrossin, Gayle, Stockman, Marybeth, Norato, Gina, Vetter, C Stephenie, et al. (2025). Post-exertional malaise in Long COVID: subjective reporting versus objective assessment.. Frontiers in neurology. https://doi.org/10.3389/fneur.2025.1534352
BibTeX
@article{mecfsatlas-stussman-2025-post-exertional,
author = {Stussman, Barbara and Camarillo, Nathan and McCrossin, Gayle and Stockman, Marybeth and Norato, Gina and Vetter, C Stephenie and Ferrufino, Alenka and Adedamola, Ashade and Grayson, Nicholas and Nath, Avindra and Chan, Leighton and Walitt, Brian and Chin, Lisa M K},
title = {Post-exertional malaise in Long COVID: subjective reporting versus objective assessment.},
journal = {Frontiers in neurology},
year = {2025},
doi = {10.3389/fneur.2025.1534352},
note = {PubMed: 40337174},
url = {https://www.mecfsatlas.com/evidence/stussman-2025-post-exertional},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-29. https://www.mecfsatlas.com/evidence/stussman-2025-post-exertional
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