Blackwood, S K, MacHale, S M, Power, M J et al. · Journal of neurology, neurosurgery, and psychiatry · 1998 · DOI
This study compared how people with ME/CFS, people with depression, and healthy people performed on thinking and strength tests before and after exercise on a treadmill. People with ME/CFS reported feeling much more tired and struggling harder during the exercise than the other groups. After exercising, people with ME/CFS had bigger drops in their ability to focus and pay attention compared to healthy people, suggesting that exercise affects their thinking ability in a specific way.
This study provides objective evidence that cognitive function in ME/CFS is specifically impaired by exertion, supporting patients' reports of post-exertional malaise. Understanding the mechanisms of cognitive impairment after activity may help identify underlying biological differences in ME/CFS and inform treatment approaches that avoid worsening symptoms.
This study does not prove that reduced working memory capacity is the cause of post-exertional cognitive decline—it only suggests this as a possible mechanism. The small sample size and cross-sectional design mean findings may not apply broadly to all ME/CFS patients, and the study does not establish whether cognitive deficits persist beyond the immediate post-exercise period or worsen with repeated exertion.
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
Blackwood, S K, MacHale, S M, Power, M J, Goodwin, G M, & Lawrie, S M (1998). Effects of exercise on cognitive and motor function in chronic fatigue syndrome and depression.. Journal of neurology, neurosurgery, and psychiatry. https://doi.org/10.1136/jnnp.65.4.541
BibTeX
@article{mecfsatlas-blackwood-1998-effects-exercise,
author = {Blackwood, S K and MacHale, S M and Power, M J and Goodwin, G M and Lawrie, S M},
title = {Effects of exercise on cognitive and motor function in chronic fatigue syndrome and depression.},
journal = {Journal of neurology, neurosurgery, and psychiatry},
year = {1998},
doi = {10.1136/jnnp.65.4.541},
note = {PubMed: 9771781},
url = {https://www.mecfsatlas.com/evidence/blackwood-1998-effects-exercise},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/blackwood-1998-effects-exercise
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