Cambras, Trinitat, Domingo, Joan Carles, Sanmartín-Sentañes, Ramon et al. · Journal of translational medicine · 2026 · DOI
This study observed patterns of light exposure in 100 ME/CFS patients and 56 healthy controls over one week, using wrist-worn devices to track light, activity, and body temperature. Researchers found that ME/CFS patients with more stable daytime light exposure reported lower fatigue, better sleep, and higher quality of life compared to those with irregular or nighttime-dominant light patterns; these associations were not observed in healthy controls. The findings suggest light exposure patterns may be worth studying as a potentially modifiable lifestyle factor, though the study cannot prove that changing light exposure would improve symptoms.
ME/CFS patients commonly report disrupted circadian rhythms and poor sleep; this study identified specific light-exposure patterns that are associated with symptom variation in this population. Light exposure is potentially modifiable through behaviour, making it a candidate target for low-risk lifestyle interventions if future controlled studies confirm benefit. The finding that light associations differ between ME/CFS and healthy controls suggests light-related circadian dysregulation may be part of ME/CFS illness patterns.
This cross-sectional design does not establish that light exposure patterns cause symptom severity or that changing light exposure will improve outcomes. The study does not confirm a mechanism (e.g., circadian, metabolic, or immune) linking light patterns to ME/CFS symptoms. The findings do not yet support light-exposure modification as a treatment recommendation without prospective or interventional evidence.
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
Cambras, Trinitat, Domingo, Joan Carles, Sanmartín-Sentañes, Ramon, Alegre-Martín, José, & Castro-Marrero, Jesús (2026). Association between light exposure patterns and multidimensional health outcomes in individuals with myalgic encephalomyelitis/chronic fatigue syndrome: findings from an observational cross-sectional cohort study.. Journal of translational medicine. https://doi.org/10.1186/s12967-026-08556-6
BibTeX
@article{mecfsatlas-cambras-2026-association-between,
author = {Cambras, Trinitat and Domingo, Joan Carles and Sanmartín-Sentañes, Ramon and Alegre-Martín, José and Castro-Marrero, Jesús},
title = {Association between light exposure patterns and multidimensional health outcomes in individuals with myalgic encephalomyelitis/chronic fatigue syndrome: findings from an observational cross-sectional cohort study.},
journal = {Journal of translational medicine},
year = {2026},
doi = {10.1186/s12967-026-08556-6},
note = {PubMed: 42399727},
url = {https://www.mecfsatlas.com/evidence/cambras-2026-association-between},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-07-08. https://www.mecfsatlas.com/evidence/cambras-2026-association-between
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