"Long before it's in the papers"
January 27, 2015


Office windows may boost health

Aug. 11, 2014
Courtesy of Northwestern University
and World Science staff

Of­fice work­ers with more light ex­po­sure at the of­fice slept more and bet­ter at night, were more phys­ic­ally ac­tive and had bet­ter qual­ity of life than oth­ers, ac­cord­ing to a stu­dy that looked at a small sam­ple of workers.

The re­search was re­ported in the Jour­nal of Clin­i­cal Sleep Med­i­cine in June.

“There is in­creas­ing ev­i­dence that ex­po­sure to light, dur­ing the day, par­tic­u­larly in the morn­ing, is ben­e­fi­cial to your health via its ef­fects on mood, alert­ness and metabolis­m,” said sen­ior study au­thor Phyl­lis Zee, a neu­rol­o­gist and sleep spe­cial­ist at North­west­ern Uni­vers­ity in Ev­ans­ton, Ill.

“Work­ers are a group at risk be­cause they are typ­ic­ally in­doors of­ten with­out ac­cess to nat­u­ral or even ar­ti­fi­cial bright light for the en­tire day,” said Zee, who is al­so di­rec­tor of the Sleep Dis­or­ders Cen­ter at North­west­ern Me­mo­ri­al Hos­pi­tal.

“Ar­chi­tects need to be aware of the im­por­tance of nat­u­ral light not only in terms of their po­ten­tial en­er­gy sav­ings but al­so in terms of af­fect­ing oc­cu­pants’ health,” said co-lead au­thor Mo­hamed Bou­be­kri, an ar­chi­tect at the Uni­vers­ity of Il­li­nois at Urbana-Cham­paign. Work­sta­t­ions should be with­in 20 to 25 feet of the out­er walls con­tain­ing the win­dows, he added.

The re­search­ers stud­ied 49 day-shift of­fice work­ers, 27 in win­dow­less work­places and 22 in work­places with win­dows. Em­ploy­ees with win­dows in the work­place re­ceived 173 pe­r­cent more white light ex­po­sure dur­ing work hours and slept an av­er­age of 46 min­utes more per night, the study found.

Health-related qual­ity of life and sleep qual­ity were meas­ured with a self-re­ported form and sleep qual­ity was eval­u­at­ed us­ing a ques­tion­naire called the Pitts­burgh Sleep Qual­ity In­dex. Some par­ti­ci­pants al­so wore a wrist mon­i­tor that meas­ured light ex­po­sure, ac­ti­vity and sleep.

While the sleep-related find­ings were statistically sig­ni­fi­cant, the find­ings regarding phys­ical activity weren’t strong enough to reach stat­ist­ical signifi­cance, ac­cord­ing to the re­port.

“Light is the most im­por­tant syn­chro­niz­ing agent for the brain and body,” said Ivy Che­ung, co-lead au­thor and doc­tor­al can­di­date in neu­ro­sci­ence in Zee’s lab at North­west­ern. “Prope­r syn­chron­iz­a­tion of your in­ter­nal bi­o­log­i­cal rhythms with the earth’s daily rota­t­ion has been shown to be es­sen­tial for health.”

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Office workers with more light exposure at the office slept more and better, were more physically active and had better quality of life than others, according to a study. The research was reported in the Journal of Clinical Sleep Medicine in June. “There is increasing evidence that exposure to light, during the day, particularly in the morning, is beneficial to your health via its effects on mood, alertness and metabolism,” said senior study author Phyllis Zee, a neurologist and sleep specialist at Northwestern University in Evanston, Ill. “Workers are a group at risk because they are typically indoors often without access to natural or even artificial bright light for the entire day,” said Zee, who is also director of the Sleep Disorders Center at Northwestern Memorial Hospital. “Architects need to be aware of the importance of natural light not only in terms of their potential energy savings but also in terms of affecting occupants’ health,” said co-lead author Mohamed Boubekri, an architect at the University of Illinois at Urbana-Champaign. Workstations should be within 20 to 25 feet of the outer walls containing the windows, he added. The researchers studied a sample of workers that included 49 day-shift office workers, 27 in windowless workplaces and 22 in workplaces with windows. Employees with windows in the workplace received 173 percent more white light exposure during work hours and slept an average of 46 minutes more per night, the study found. Health-related quality of life and sleep quality were measured with a self-reported form and sleep quality was evaluated using a questionnaire called the Pittsburgh Sleep Quality Index. Some participants also wore a wrist monitor that measured light exposure, activity and sleep. “Light is the most important synchronizing agent for the brain and body,” said Ivy Cheung, co-lead author and doctoral candidate in neuroscience in Zee’s lab at Northwestern. “Proper synchronization of your internal biological rhythms with the earth’s daily rotation has been shown to be essential for health.”