Sunny office
The health benefits of working in an office with plenty of natural daylight include better sleep and more physical activity

Natural light in the office improves health

12 August, 2014

Natural Health News — Office workers with more natural light exposure at the office sleep better, are more physically active and enjoy a better overall quality of life, according to new data.

The study from Northwestern Medicine and the University of Illinois at Urbana-Champaign, highlights the importance of exposure to natural light to employee health and suggests that natural daylight exposure for workers should be a priority in the minds of architects who design office spaces.

The study, published in the Journal of Clinical Sleep Medicine, included 49 day-shift office workers; 27 in windowless workplaces and 22 in workplaces with windows. Health-related quality of life and sleep quality were measured via a self-reported survey.

In addition 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. Actigraphy is a single device worn on the wrist that gives measures of light exposure as well as activity and sleep.

Let there be light

Employees with windows in the workplace received 173% more white light exposure during work hours and slept an average of 46 minutes more per night than those who did not have the natural light exposure in the workplace.

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

Workers without windows had poorer scores 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 study author Phyllis Zee, MD, 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.”

Redesigning office spaces

Co-lead author Mohamed Boubekri, an associate professor of architecture at the University of Illinois at Urbana-Champaign added, “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

A simple design solution to augment daylight penetration in office buildings would be to make sure the workstations are within 20 to 25 feet of the peripheral walls containing the windows, because, as Boubekri notes, “Daylight from side windows almost vanishes after 20 to 25 feet from the windows.”

“Light is the most important synchronising agent for the brain and body,” said Ivy Cheung, co-lead author and PhD 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.”

In addition , the authors note, people who get more light during the day may sleep better at night, which can also help improve health.