Riley, M S, O'Brien, C J, McCluskey, D R et al. · BMJ (Clinical research ed.) · 1990 · DOI
This study tested how much physical activity patients with ME/CFS could manage on a treadmill and compared them to healthy people and those with irritable bowel syndrome. Researchers found that ME/CFS patients got tired much faster, had higher heart rates during exercise, and felt like they were working much harder than the other groups—even though they weren't doing as much activity.
This study provides objective physiological evidence that ME/CFS involves genuine reduced exercise capacity with altered metabolic responses, not simply deconditioning or psychological factors. Understanding the specific aerobic and lactate abnormalities during exertion helps validate patient experiences and informs discussions about exercise safety.
This study does not prove what *causes* the reduced aerobic capacity or metabolic abnormalities—it only documents that they exist. It does not establish whether these findings persist long-term or change with different interventions, nor does it distinguish between primary pathophysiology and secondary effects of illness.
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
Riley, M S, O'Brien, C J, McCluskey, D R, Bell, N P, & Nicholls, D P (1990). Aerobic work capacity in patients with chronic fatigue syndrome.. BMJ (Clinical research ed.). https://doi.org/10.1136/bmj.301.6758.953
BibTeX
@article{mecfsatlas-riley-1990-aerobic-work,
author = {Riley, M S and O'Brien, C J and McCluskey, D R and Bell, N P and Nicholls, D P},
title = {Aerobic work capacity in patients with chronic fatigue syndrome.},
journal = {BMJ (Clinical research ed.)},
year = {1990},
doi = {10.1136/bmj.301.6758.953},
note = {PubMed: 2249024},
url = {https://www.mecfsatlas.com/evidence/riley-1990-aerobic-work},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/riley-1990-aerobic-work
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