Critical care (London, England)Jul 3, 2026

Detailed monitoring shows interrupted 24-hour light exposure in intensive care units

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗OA ↗

Updated Jul 4, 2026

Abstract

High-resolution monitoring revealed fragmented light exposure patterns in critically ill patients over a 24-hour period.

Light is a significant factor in regulating sleep and neuroendocrine functions.
Abnormal light exposure is linked to delirium and negative outcomes in ICU patients.
Previous studies typically measured light exposure with low resolution, missing important details.
Routine ICU care often involves brief but frequent light exposure due to necessary interventions.
The patterns of light exposure and its fragmentation during nighttime were not well understood prior to this study.

Simplified

Light is a key regulator of circadian rhythms, sleep, and neuroendocrine function. Abnormal light exposure has been associated with delirium and adverse outcomes in critically ill patients. While previous ICU studies have generally reported low daytime illuminance and intermittent nocturnal light exposure, most relied on averaged measurements or low temporal resolution monitoring, potentially obscuring clinically relevant exposure patterns. In routine ICU care, light exposure often occurs as brief but frequent events related to necessary interventions, yet the extent and temporal structure of such light fragmentation remain poorly characterized. This study therefore aimed to characterize high-resolution 24-hour light exposure patterns and nocturnal fragmentation in ICU patients.