Employees with more exposure to natural light at the office sleep longer, have higher quality sleep, are more physically active, and have a better quality of life, according to new research.
The study highlights the importance of natural light to employee health, according to researchers from Northwestern Medicine and the University of Illinois at Urbana-Champaign. It also spotlights the priority architects should place on creating an office environment that provides plenty of natural daylight exposure for workers, the researchers note.
In the study, researchers found that employees with windows received 173 percent more white light exposure during work hours and slept an average of 46 minutes more per night than employees who did not have natural light exposure in the workplace. There also was a trend for workers in offices with windows to be more physically active, the researchers noted.
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 and sleep disturbances.
“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 author Phyllis Zee, M.D., a Northwestern Medicine neurologist and sleep specialist.
“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. The study results confirm that light during the natural daylight hours has powerful effects on health.”
“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, Ph.D., an associate professor of architecture at the University of Illinois at Urbana-Champaign.
“A simple design solution to augment daylight penetration in office buildings would be to make sure that workstations are within 20 to 25 feet of the peripheral walls containing the windows,” he noted.
“Daylight from side windows almost vanishes after 20 to 25 feet from the windows,” he said.
The study group included 49 day-shift office workers, with 27 in windowless workplaces and 22 in workplaces with windows. Health-related quality of life and sleep quality were measured with a self-reported form. Sleep quality was evaluated with the Pittsburgh Sleep Quality Index (PSQI).
Light exposure, activity, and sleep were measured by actigraphy in a subset of 21 participants, including 10 in windowless workplaces and 11 in workplaces with windows. Actigraphy is a device worn on the wrist that measures light exposure, as well as activity and sleep, the researchers explain.
“Light is the most important synchronizing agent for the brain and body,” said Ivy Cheung, co-lead author and a Ph.D. 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.”
“Also, people who get more light during the day may sleep better at night, which can also help improve health,” Zee concluded.
The study was published in the Journal of Clinical Sleep Medicine.
Source: Northwestern University