Daylight exposure has ‘remarkable’ effect on office workers’ health

The architectural design of office environments should take into consideration how natural daylight exposure contributes to employee wellness say the authors of a new study which observes a strong relationship between workplace daylight exposure and office workers’ health. Compared to workers in offices without windows, those with windows in the workplace received 173 per cent more white light exposure during work hours and slept an average of 46 minutes more per night. 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.

There also was a trend for workers in offices with windows to have more physical activity than those without windows.

“The extent to which daylight exposure impacts office workers is remarkable,” said study co-author Ivy Cheung, a doctoral candidate in the Interdepartmental Neuroscience program at Northwestern University in Chicago, Ill.

“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,” said Cheung.

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 research was published in an online supplement of the journal SLEEP, and presented last week at SLEEP 2013, the 27th annual meeting of the Associated Professional Sleep Societies LLC, which took place in Baltimore in the U.S.