Orjatsalo, Maija, Alakuijala, Anniina, Partinen, Markku · Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine · 2018 · DOI
This study examined how the nervous system controls heart rate and blood pressure during sleep in ME/CFS patients compared to people without the condition. Researchers found that ME/CFS patients showed unusual patterns during sleep: their sympathetic nervous system (the 'fight or flight' system) was more active than normal, while their parasympathetic nervous system (the 'rest and digest' system) was less active, especially during deep sleep. This abnormal nervous system activity during sleep may help explain why ME/CFS patients often wake up feeling unrefreshed.
Unrefreshing sleep is a hallmark symptom of ME/CFS, yet its biological basis remains poorly understood. This study provides objective evidence of autonomic nervous system dysfunction during sleep in ME/CFS, suggesting that abnormal nervous system regulation—rather than simply poor sleep quantity or quality—may underlie sleep-related symptoms. Understanding these mechanisms could guide development of targeted treatments to improve sleep quality and overall functioning.
This small case series (n=8 per group) cannot establish whether ANS dysfunction causes unrefreshing sleep or results from it. The study does not prove that correcting these ANS abnormalities would improve sleep quality or fatigue. Additionally, it does not determine whether these findings apply broadly to all ME/CFS patients, as generalizability is limited by the small, age-restricted sample and lack of standardized control group definitions.
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
Orjatsalo, Maija, Alakuijala, Anniina, & Partinen, Markku (2018). Autonomic Nervous System Functioning Related to Nocturnal Sleep in Patients With Chronic Fatigue Syndrome Compared to Tired Controls.. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine. https://doi.org/10.5664/jcsm.6924
BibTeX
@article{mecfsatlas-orjatsalo-2018-autonomic-nervous,
author = {Orjatsalo, Maija and Alakuijala, Anniina and Partinen, Markku},
title = {Autonomic Nervous System Functioning Related to Nocturnal Sleep in Patients With Chronic Fatigue Syndrome Compared to Tired Controls.},
journal = {Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine},
year = {2018},
doi = {10.5664/jcsm.6924},
note = {PubMed: 29246267},
url = {https://www.mecfsatlas.com/evidence/orjatsalo-2018-autonomic-nervous},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/orjatsalo-2018-autonomic-nervous
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