U.S. Department of State Headquarters Building Lighting Intervention

GSA collaborated with the U.S. Department of State (DoS) to measure daytime alertness, energy and vitality levels of participants working in three headquarters buildings in Washington, DC to see if circadian-effective lighting delivered from LED lights could provide health benefits when they are needed the most: at work during the day.

GSA conducted a 3-week lighting intervention by placing tunable LED lights on the desktops of study participants. The LED lights were programmed to deliver saturated blue light in the morning (6:00 a.m. to 12:00 p.m.), white light at midday (12:00 p.m. to 1:30 p.m.), and saturated red light in the afternoon (1:30 p.m. to 5:00 p.m.).

Participants reported they felt less sleepy, had more energy, and were more alert during the workday with the LED desktop lights turned on. They also fell asleep faster at night and woke up earlier the next day. Finally, participants reported feeling more alert in the afternoon with the LED desktop lights turned on.

For more information, view the technical report:

Last Reviewed: 2020-09-16