Vergauwen, Kuni, Huijnen, Ivan P J, Smeets, Rob J E M et al. · Journal of psychosomatic research · 2021 · DOI
This study compared two ways of measuring physical activity in women with ME/CFS: a written activity diary (where patients recorded what they did) and an accelerometer (a device that objectively tracks movement). The researchers found that the diary method was much less accurate in ME/CFS patients compared to healthy people. Interestingly, factors like symptom severity or quality of life didn't explain why the diary was unreliable—suggesting ME/CFS itself may affect how accurately patients can report their own activity levels.
Accurate activity measurement is critical for ME/CFS research and clinical management, yet this study reveals that patient-reported activity may substantially misrepresent actual physical output. This finding has implications for designing reliable clinical trials and interpreting patient-reported outcomes in ME/CFS studies. Understanding the gap between perceived and objective activity may also inform symptom management strategies and realistic activity counseling.
This study does not prove that ME/CFS patients intentionally misreport activity or lack self-awareness. It also does not explain the biological or cognitive mechanisms underlying the discrepancy between perceived and measured activity. The findings are limited to women and may not generalize to men with ME/CFS, and causality cannot be established in this cross-sectional design.
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
Vergauwen, Kuni, Huijnen, Ivan P J, Smeets, Rob J E M, Kos, Daphne, van Eupen, Inge, Nijs, Jo, et al. (2021). An exploratory study of discrepancies between objective and subjective measurement of the physical activity level in female patients with chronic fatigue syndrome.. Journal of psychosomatic research. https://doi.org/10.1016/j.jpsychores.2021.110417
BibTeX
@article{mecfsatlas-vergauwen-2021-exploratory-study,
author = {Vergauwen, Kuni and Huijnen, Ivan P J and Smeets, Rob J E M and Kos, Daphne and van Eupen, Inge and Nijs, Jo and Meeus, Mira},
title = {An exploratory study of discrepancies between objective and subjective measurement of the physical activity level in female patients with chronic fatigue syndrome.},
journal = {Journal of psychosomatic research},
year = {2021},
doi = {10.1016/j.jpsychores.2021.110417},
note = {PubMed: 33773330},
url = {https://www.mecfsatlas.com/evidence/vergauwen-2021-exploratory-study},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/vergauwen-2021-exploratory-study
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