Human-Centric Lighting
VideodeLIGHTed Talks #8: Good Light – Good Sleep
Full recording of deLIGHTed Talks #8, held online by LpS DIGITAL on 24 April 2025 (91 minutes). Dr. Renske Lok (Stanford University) shows that bright light during the day deepens nighttime sleep, reduces nighttime awakenings, improves sleep efficiency and lowers next-day sleep inertia. Dr. Jeffrey Hubbard (University of Lausanne / EPFL) compares how light and darkness drive sleep and wakefulness in nocturnal mice and day-active Sudanian grass rats. Chronobiologist Dr. Virginie Gabel, founder of Clock&Me, moderates the session and the discussion on what the findings mean for lighting design.
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Modern life constantly exposes us to artificial light – often at the wrong times. That can throw our internal clocks out of step and leave us tired and unproductive during the day. The eighth edition of deLIGHTed Talks, held online on 24 April 2025, looked at the science behind good light and good sleep: two researchers presented their work, followed by a discussion moderated by chronobiologist Dr. Virginie Gabel. The full 91-minute recording is available above.
The talks
How daytime light exposure shapes nighttime sleep quality – Dr. Renske Lok, Stanford University
Light does more than let us see. Its non-image-forming effects keep us alert, support cognitive performance and regulate melatonin production – and, as Dr. Lok’s laboratory experiments and field studies show, they reach into the night as well. Bright light during the day deepens sleep, reduces nighttime awakenings and improves overall sleep efficiency. It also reduces sleep inertia the next morning, so people wake up more alert.
Because most people spend the majority of their day indoors under artificial lighting, the findings matter for lighting design, workplace policies and personal sleep strategies alike.
The opposing forces of light and darkness on sleep and waking behavior – Dr. Jeffrey Hubbard, University of Lausanne / EPFL
Beyond its well-known effect on the circadian clock, light also acts directly on sleep and wakefulness. Dr. Hubbard explores these direct effects in two animal models: the nocturnal laboratory mouse and the day-active Sudanian grass rat (Arvicanthis ansorgei). Comparing them shows how the same cue – light or darkness – can produce opposite behavioral and physiological responses depending on when an animal is active, and what that means for people living in a world that never gets completely dark.
Moderation
Dr. Virginie Gabel is an internationally recognized chronobiologist and sleep scientist and the founder of Clock&Me, a consultancy that helps organizations prevent the occupational risks of sleep deprivation and circadian misalignment. She guided the discussion with insights from her own research into sleep, light and human performance.
The speakers
- Dr. Renske Lok – senior postdoctoral fellow in the Department of Psychiatry and Behavioral Sciences at Stanford University; Vice-President of the Society for Light, Rhythms and Circadian Health and science advisor to the Good Light Group.
- Dr. Jeffrey Hubbard – translational sleep researcher based in Switzerland; formerly senior scientist at the Center for Integrative Genomics of the University of Lausanne and at the Laboratory of Integrated Performance in Design at EPFL.
- Dr. Virginie Gabel (moderator) – chronobiologist, founder of Clock&Me, board member and science advisor of the Good Light Group.
About deLIGHTed Talks
deLIGHTed Talks is the LpS DIGITAL webinar series on light, health and well-being. Read the announcement of this session for the full speaker biographies and abstracts, and the following edition, deLIGHTed Talks #9: Good Light – How to Create it Indoors.
