Ohashi, K, Bleijenberg, G, van der Werf, S et al. · Methods of information in medicine · 2004
This study looked at how physical activity patterns differ between people with ME/CFS and healthy people throughout the day. Researchers used special mathematical tools to analyze activity data and found that people with ME/CFS have more sudden, abrupt stops in their activities during the day—possibly because fatigue forces them to rest unexpectedly. This pattern was not seen in healthy control subjects.
This study provides objective, quantifiable evidence of altered physical activity patterns in ME/CFS that goes beyond simple reduction in activity levels—showing a fundamental change in *how* activity is interrupted. Understanding this temporal structure may help researchers develop more precise biomarkers for ME/CFS diagnosis and could inform activity-pacing interventions by identifying the characteristic pattern of activity collapse in the condition.
This study does not establish causality—it demonstrates correlation between illness and activity interruption patterns but cannot prove whether the abrupt stops are a direct cause or consequence of ME/CFS pathology. The small sample size (10 CFS patients, 6 controls) limits generalizability. The study also does not prove the underlying physiological mechanism driving these activity patterns.
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
Ohashi, K, Bleijenberg, G, van der Werf, S, Prins, J, Amaral, L A N, Natelson, B H, et al. (2004). Decreased fractal correlation in diurnal physical activity in chronic fatigue syndrome.. Methods of information in medicine. https://pubmed.ncbi.nlm.nih.gov/15026831/
BibTeX
@article{mecfsatlas-ohashi-2004-decreased-fractal,
author = {Ohashi, K and Bleijenberg, G and van der Werf, S and Prins, J and Amaral, L A N and Natelson, B H and Yamamoto, Y},
title = {Decreased fractal correlation in diurnal physical activity in chronic fatigue syndrome.},
journal = {Methods of information in medicine},
year = {2004},
note = {PubMed: 15026831},
url = {https://www.mecfsatlas.com/evidence/ohashi-2004-decreased-fractal},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/ohashi-2004-decreased-fractal
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