PLoS Biology (Mar 2022)

Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults

  • Timothy M. Brown,
  • George C. Brainard,
  • Christian Cajochen,
  • Charles A. Czeisler,
  • John P. Hanifin,
  • Steven W. Lockley,
  • Robert J. Lucas,
  • Mirjam Münch,
  • John B. O’Hagan,
  • Stuart N. Peirson,
  • Luke L. A. Price,
  • Till Roenneberg,
  • Luc J. M. Schlangen,
  • Debra J. Skene,
  • Manuel Spitschan,
  • Céline Vetter,
  • Phyllis C. Zee,
  • Kenneth P. Wright

Journal volume & issue
Vol. 20, no. 3


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Ocular light exposure has important influences on human health and well-being through modulation of circadian rhythms and sleep, as well as neuroendocrine and cognitive functions. Prevailing patterns of light exposure do not optimally engage these actions for many individuals, but advances in our understanding of the underpinning mechanisms and emerging lighting technologies now present opportunities to adjust lighting to promote optimal physical and mental health and performance. A newly developed, international standard provides a SI-compliant way of quantifying the influence of light on the intrinsically photosensitive, melanopsin-expressing, retinal neurons that mediate these effects. The present report provides recommendations for lighting, based on an expert scientific consensus and expressed in an easily measured quantity (melanopic equivalent daylight illuminance (melaponic EDI)) defined within this standard. The recommendations are supported by detailed analysis of the sensitivity of human circadian, neuroendocrine, and alerting responses to ocular light and provide a straightforward framework to inform lighting design and practice. Light exposure influences human health and wellbeing by modulating circadian rhythms and sleep. This Consensus View outlines the first expert scientific consensus recommendations for appropriate daily patterns of light exposure to promote health and wellbeing and inform lighting design and practice.