Boruch, Alexander E, Barhorst, Ellen E, Rayne, Tessa J et al. · Brain, behavior, and immunity · 2024 · DOI
This study tested whether exercise of different intensities causes post-exertional malaise (PEM)—a worsening of symptoms after physical activity—in veterans with Gulf War Illness, a condition similar to ME/CFS. Forty participants did light, moderate, or vigorous cycling for 20 minutes, or simply rested, while researchers measured their symptoms, pain sensitivity, thinking ability, and blood markers before and after. The study found that exercise did not cause greater symptom worsening or other problems than rest, even at higher intensities.
This study directly challenges the widespread concern that exercise reliably triggers post-exertional malaise in chronic multisymptom illnesses like ME/CFS and GWI. For patients struggling with activity recommendations, these findings suggest that moderate-intensity exercise may be safer at the group level than many have feared, potentially supporting more personalized, evidence-based exercise prescriptions that could improve quality of life.
This study does not prove that PEM does not exist or that all ME/CFS/GWI patients can safely exercise at any intensity. It involved only Gulf War Illness veterans (a specific population) over a single acute session; chronic effects of repeated exercise were not assessed. Individual variation was substantial, meaning some participants did experience symptom worsening even though group-level differences were absent.
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
Boruch, Alexander E, Barhorst, Ellen E, Rayne, Tessa J, Roberge, Gunnar A, Brukardt, Sailor M, Leitel, Zoie T, et al. (2024). Exercise does not cause post-exertional malaise in Veterans with Gulf War Illness: A randomized, controlled, dose-response, crossover study.. Brain, behavior, and immunity. https://doi.org/10.1016/j.bbi.2024.05.026
BibTeX
@article{mecfsatlas-boruch-2024-exercise-does,
author = {Boruch, Alexander E and Barhorst, Ellen E and Rayne, Tessa J and Roberge, Gunnar A and Brukardt, Sailor M and Leitel, Zoie T and Coe, Christopher L and Fleshner, Monika and Falvo, Michael J and Cook, Dane B and Lindheimer, Jacob B},
title = {Exercise does not cause post-exertional malaise in Veterans with Gulf War Illness: A randomized, controlled, dose-response, crossover study.},
journal = {Brain, behavior, and immunity},
year = {2024},
doi = {10.1016/j.bbi.2024.05.026},
note = {PubMed: 38777281},
url = {https://www.mecfsatlas.com/evidence/boruch-2024-exercise-does},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-27. https://www.mecfsatlas.com/evidence/boruch-2024-exercise-does
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