Office Lighting, Alertness, and Sleep (12-13-19)

Researchers at the Lighting Research Center (LRC) at Rensselaer and the US General Services Administration (GSA) conducted important research related to at-work alertness and nighttime sleep.  During their study “luminaires, mounted near the participants’ computer monitors provided: (1) morning saturated blue light delivering a circadian stimulus (CS) of 0.4, (2) midday polychromatic white light delivering a CS of 0.3, and (3) afternoon saturated red light delivering a CS close to zero. . . . participants exhibited more consolidated rest–activity patterns, indicating better circadian entrainment, and woke up earlier during the intervention compared to baseline. The morning blue light appears to have advanced participants’ circadian phase, causing participants to wake up earlier in the morning. The afternoon red light elicited an acute alerting response close to the post-lunch dip (around 3 p.m.), reducing subjective sleepiness and increasing subjective vitality and energy. . . . The study results showed that office workers felt much less sleepy with the use of supplemental electric lighting and, as hypothesized, they also reported feeling significantly more vital, energetic, and alert compared to baseline.”  Tools available at the Rensselaer website provide important guidance for implementing these findings as well as useful background information and definitions.

“LRC Research Collaboration with GSA Finds Morning Blue Light and Afternoon Red Light Promote Entrainment and Increase Alertness in Office Workers.”  2019.  Press release, Lighting Research Center, Rensselaer Polytechnic Institute, https://www.lrc.rpi.edu/resources/newsroom/pr_story.asp?id=450#.XfeVry2ZNo5