Workplace Daylight Exposure Linked to Sleep, Activity and Quality of Life

A study published in the journal Sleep shows a strong association between workplace daylight exposure and the worker's sleep, activity and quality of life.

When compared to workers who work in an office without windows, those with windows at their workplace received at least 173 percent more white light exposure while at work and slept on an average of 46 minutes extra per night.

Those who worked in offices with windows engaged in 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.

To prove the finding, researchers conducted a study on 49 day shift workers, out of which 27 worked in windowless offices and 22 worked in offices with windows. With the help of the Short Form-3 (SF-36), researchers measured the health-related quality of life, and the quality of sleep with Pittsburgh Sleep Quality Index (PSQI). They also measured the person's exposure to light, activity and their sleep with actigraphy in a set of 21 participants, with 10 in windowless workplaces and 11 in workplaces that had windows.

The authors state that the architectural design of the office environment must consider how exposure to natural daylight can add to the employee's wellness.

On conducting the study, they also noticed that workers who worked in offices without windows scored terribly on quality of life measures that were related to physical problems and vitality, when compared to those with windows. They also had poor results on measures of overall sleep quality, sleep efficiency, disturbances in sleep and impaired functioning during daytime.

"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 findings will be presented Tuesday, June 4, in Baltimore, Md., at SLEEP 2013, the 27th annual meeting of the Associated Professional Sleep Societies LLC.