Updated on 6 June 2013
Northwestern University study - People who worked in offices with windows received 173 percent more white light during work and slept more every night
Singapore: A new study by Northwestern University in Chicago, US, has demonstrated a strong relationship between workplace daylight exposure and office workers' sleep, activity and quality of life. The research was published recently in an online supplement of the journal Sleep.
The study group comprised 49 day-shift office workers, 27 in windowless workplaces and 22 in workplaces with windows. Health-related quality of life was measured using the Short Form-36 (SF-36), and sleep quality was evaluated with the Pittsburgh Sleep Quality Index (PSQI). Light exposure, activity and sleep were measured by actigraphy in a representative subset of 21 participants - 10 in windowless workplaces and 11 in workplaces with windows.
The study highlighted that as compared to workers in offices without windows, those 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. There also was a trend for workers in offices with windows to have more physical activity than those without windows.
Moreover, workers without windows reported poorer scores than their counterparts on quality of life measures related to physical problems and vitality, as well as poorer outcomes on measures of overall sleep quality, sleep efficiency, sleep disturbances and daytime dysfunction.
Ms Ivy Cheung, study co-author and a doctoral candidate in the Interdepartmental Neuroscience program at Northwestern University in Chicago, US, said that, "The extent to which daylight exposure impacts office workers is remarkable. Day-shift office workers' quality of life and sleep may be improved via emphasis on light exposure and lighting levels in current offices as well as in the design of future offices."