Personalized office lighting for circadian health and improved sleep

Charikleia Papatsimpa (Corresponding author), Jean Paul Linnartz

Research output: Contribution to journalArticleAcademicpeer-review

30 Citations (Scopus)

Abstract

In modern society, the average person spends more than 90% of their time indoors. However, despite the growing scientific understanding of the impact of light on biological mechanisms, the existing light in the built environment is designed predominantly to meet visual performance requirements only. Lighting can also be exploited as a means to improve occupant health and well‐being through the circadian functions that regulate sleep, mood, and alertness. The benefits of well‐lit spaces map across other regularly occupied building types, such as residences and schools, as well as patient rooms in healthcare and assisted‐living facilities. Presently, Human Centric Lighting is being offered based on generic insights on population average experiences. In this paper, we suggest a personalized bio‐adaptive office lighting system, controlled to emit a lighting recipe tailored to the individual employee. We introduce a new mathematical optimization for lighting schedules that align the 24‐hour circadian cycle. Our algorithm estimates and optimizes parameters in experimentally validated models of the human circadian pacemaker. Moreover, it constrains deviations from the light levels desired and needed to perform daily activities. We further translate these into general principles for circadian lighting. We use experimentally validated models of the human circadian pacemaker to introduce a new algorithm to mathematically optimize lighting schedules to achieve circadian alignment to the 24‐hour cycle, with constrained deviations from the light levels desired for daily activities. Our suggested optimization algorithm was able to translate our findings into general principles for circadian lighting. In particular, our simulation results reveal: (1) how energy constrains drive the shape of optimal lighting profiles by dimming the light levels in the time window that light is less biologically effective; (2) how inter‐individual variations in the characteristic internal duration of the day shift the timing of optimal lighting exposure; (3) how user habits and, in particular, late‐evening light exposure result in differentiation in late afternoon office lighting.

Original languageEnglish
Article number4569
Number of pages17
JournalSensors
Volume20
Issue number16
DOIs
Publication statusPublished - 14 Aug 2020

Funding

Funding: This work is part of the research program “OPTILIGHT: Mathematical Optimizations for Human Centric Lighting” with project number 14671, which is partly financed by the Netherlands Organization for Scientific Research (NWO), and which is conducted in the context of a bilateral cooperation between TU/e and Signify in the Intelligent Lighting Institute (ILI).

Keywords

  • Circadian clock
  • Circadian light
  • Office
  • Sleep
  • Smart buildings

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