Glass, Jennifer M, Lyden, Angela K, Petzke, Frank et al. · Journal of psychosomatic research · 2004 · DOI
This study looked at whether stopping exercise for just one week could trigger pain, fatigue, or mood problems in healthy people who exercise regularly. Researchers found that 8 out of 18 fit volunteers developed these symptoms after a week without exercise, and these people had weaker stress-response systems (measured by cortisol levels, immune cells, and heart rate patterns) at the start of the study. This suggests some healthy people may naturally have less active biological stress systems and may actually rely on regular exercise to keep their symptoms suppressed.
This study offers a novel mechanistic hypothesis for ME/CFS pathogenesis: that some individuals may have underlying biological vulnerabilities (dysregulated stress responses) that remain silent until a stressor disrupts compensatory behaviors like exercise. Understanding whether exercise functions as a symptom suppressant in susceptible individuals could inform prevention strategies and explain post-exertional malaise mechanisms in ME/CFS.
This study does not prove that exercise deprivation causes ME/CFS, only that some healthy people develop temporary symptoms when they stop exercising. The findings are correlational—lower baseline stress-response markers were associated with symptom emergence, but causation is not established. The one-week timeframe and small sample size mean results cannot be generalized to the broader population or applied directly to actual ME/CFS disease development.
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
Glass, Jennifer M, Lyden, Angela K, Petzke, Frank, Stein, Phyllis, Whalen, Gail, Ambrose, Kirsten, et al. (2004). The effect of brief exercise cessation on pain, fatigue, and mood symptom development in healthy, fit individuals.. Journal of psychosomatic research. https://doi.org/10.1016/j.jpsychores.2004.04.002
BibTeX
@article{mecfsatlas-glass-2004-effect-brief,
author = {Glass, Jennifer M and Lyden, Angela K and Petzke, Frank and Stein, Phyllis and Whalen, Gail and Ambrose, Kirsten and Chrousos, George and Clauw, Daniel J},
title = {The effect of brief exercise cessation on pain, fatigue, and mood symptom development in healthy, fit individuals.},
journal = {Journal of psychosomatic research},
year = {2004},
doi = {10.1016/j.jpsychores.2004.04.002},
note = {PubMed: 15518675},
url = {https://www.mecfsatlas.com/evidence/glass-2004-effect-brief},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-25. https://www.mecfsatlas.com/evidence/glass-2004-effect-brief
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