Ludwig, Birgit, Hauer, Lea, Böck, Marion et al. · Sleep medicine · 2025 · DOI
Researchers tested whether bright light therapy—using special light boxes at home for two weeks—could help reduce fatigue in ME/CFS patients. While fatigue scores did improve immediately after the light therapy, these improvements did not remain significant when compared fairly to a waitlist control group. The study did find that bright light therapy may have helped patients concentrate better and react faster to tasks.
ME/CFS patients urgently need effective treatments for disabling fatigue. This rigorous randomized controlled design with crossover methodology provides high-quality evidence about bright light therapy's actual efficacy, helping patients and clinicians make informed treatment decisions and highlighting the importance of placebo control in ME/CFS intervention trials.
This study does not prove that bright light therapy is ineffective for all ME/CFS patients or in longer treatment periods—only that 2 weeks of treatment did not produce sustained fatigue reduction in this specific sample. The improvement in attention does not necessarily translate to clinically meaningful functional benefits in daily life. The high rate of postural tachycardia comorbidity limits generalizability to all ME/CFS populations.
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
Ludwig, Birgit, Hauer, Lea, Böck, Marion, Schillerwein-Kral, Cornelia, Weyer, Lena, Moser, Doris, et al. (2025). Assessing fatigue in myalgic encephalomyelitis/chronic fatigue syndrome patients before and after treatment with bright light therapy: A prospective randomized controlled crossover study.. Sleep medicine. https://doi.org/10.1016/j.sleep.2025.03.003
BibTeX
@article{mecfsatlas-ludwig-2025-assessing-fatigue,
author = {Ludwig, Birgit and Hauer, Lea and Böck, Marion and Schillerwein-Kral, Cornelia and Weyer, Lena and Moser, Doris and Zehetmayer, Sonja and Trimmel, Karin and Seidel, Stefan},
title = {Assessing fatigue in myalgic encephalomyelitis/chronic fatigue syndrome patients before and after treatment with bright light therapy: A prospective randomized controlled crossover study.},
journal = {Sleep medicine},
year = {2025},
doi = {10.1016/j.sleep.2025.03.003},
note = {PubMed: 40120538},
url = {https://www.mecfsatlas.com/evidence/ludwig-2025-assessing-fatigue},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-27. https://www.mecfsatlas.com/evidence/ludwig-2025-assessing-fatigue
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