Does Proper Light = Better Living?

At the Strategies in Light conference, experts revealed how lighting can improve feelings of alertness and well-being at work.

[dropcap style=”letter” size=”52″ bg_color=”#ffffff” txt_color=”#22d8d8″]T[/dropcap]here has been a lot of talk about “human-centric” lighting in the industry lately, but it’s more than just a buzzword. Studies are being conducted by various organizations to evaluate how artificial and natural light can be utilized to affect workers’ productivity and overall health.

Whether your employees spend the majority of their time at their desks doing paperwork, are looking at a computer screen, or are in a space with only overhead lighting, these experts say there are steps that can be taken to improve their mood and health.     

One of those studies was conducted by Dr. Judith Heerwagen, a research psychologist at the federal government’s Office of Federal High-Performance Buildings, U.S. General Services Administration (GSA), which helps federal agencies build and acquire office space, products, and other workspace services. Heerwagen and her colleague Bryan Steverson, Project Manager for GSA Workplace Research, collaborated with the Lighting Research Center (LRC) at the Rensselaer Polytechnic Institute (RPI) on the study.

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“Daylight is a critical psychological and aesthetic resource and can improve circadian health.”


According to Heerwagen, at the forefront of the research were the questions, “What can we do in the build environment to improve health?” and “Can we intentionally design indoor lighting to enhance circadian functioning for health and well-being?”

A core belief was that many people are not getting enough of the right kind of light at the right time. As a result, their circadian rhythms are being disrupted, leading to, among other conditions, daytime sleepiness and that dreaded 3 p.m. crash in energy that most office workers experience.  To remedy the situation, however, will take much more than merely getting the often-cited eight hours of sleep per night.

Who cares? The GSA for one. Why? It operates 8,700 buildings spanning 374 rentable square feet and employing thousands of people. Consider the statistic that most people spend 90 percent of their lives indoors, and you can imagine why there is concern we might not be receiving as much of Mother Nature’s benefits as our ancestors did.

The study was conducted in GSA buildings nationwide and included both winter and summer months to provide seasonal balance.

The research team performed photometric analysis of each individual’s light exposure and tracked how much they moved during the day (using a small actigraph sensor unit similar to a Fitbit®), plus employed a Daysimeter on a stick (at the windows) to track light exposure in the workspace throughout the day. Nightly sleep quality was also part of the equation. There were three key findings:

1 “We found study participants got more light at work than anywhere else — even in summer,” Heerwagen revealed, adding, “This surprised us!”

2 “Those with the most circadian stimulus – especially in the morning – had a significantly better sleep at night and were less depressed,” she noted.

3 “But many did not receive sufficient light during the day and were essentially in biological darkness,” Heerwagen said.

What was causing the reduction in light exposure had to do with the employees’ necessity to work on computer screens. To avoid glare, window shades were used to reduce the amount of daylight coming in.

“This is just the beginning of our research,” Heerwagen stated. The results of Phase 1 of the study pointed out that achieving sufficient circadian stimulus with daylight alone is difficult. “But daylight is a critical psychological and aesthetic resource and can improve circadian health if designed with the indoor ‘eco-system’ in mind,” she said.

How can the circadian stimulus be improved indoors? To find out if the answer might be through artificial lighting, the research team gave each participant a desktop lamp in a choice of white or blue light, depending on personal preference.

The desktop was the obvious choice, the researchers said, because that is where participants spent most of their work day, facing forward and concentrating on their computer screens. The desk lamps were to be on during the entire work day.

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“Employees using the desk lamps reported increased vitality, were feeling more energetic, more alert and awake, and were experiencing more energy in the afternoon.”


“We wanted something in place that could [enter] the retina, rather than hitting the side of the eye or the top of the head,” Heerwagen explained. “Our study question was, ‘Can light delivered at the desktop enhance sleep quality, alertness, and sense of vitality?’ We positioned the light at eye level and had the same stimulus for white or blue light.”

The results surprised everyone. After just two days, employees using the desk lamps reported increased vitality, were feeling more energetic, more alert and awake, and were experiencing more energy in the afternoon.

The project concluded that there needs to be more testing done so there can be consensus on the link between indoor light and health. Researchers hope that their findings will translate into product design, interior design, and operational practices that take these factors into account. Among the goals is to “form a multi-disciplinary coalition of experts that can work with standards organizations to integrate health-promoting lighting practices into existing standards.”

Dr. Larry Sadwick, Co-Founder and Chief Technology Officer for component and device developer InnoSys Inc. continued the discussion on personal workspace lighting, noting the importance of bringing task lighting down to eye level.

“There are a lot of poor products out there that cause flicker and glare,” Sadwick said, warning, “Just because [a product may be] LED, doesn’t mean it’s good.”

Another crucial element for good, efficient office lighting is to incorporate sensors that can detect motion, sound, occupancy, light, and spectral intensity.  “Glare and flicker are still major concerns,”
Sadwick stated.

Most of the systems in commercial spaces have centralized controls (other than on/off/dim) or no controls for personalized lighting such as task lights. For maximum comfort, Sadwick recommended tunable light with at least two temperature choices. “The more channels, the better, but the higher the cost,” he commented.

Sadwick recommended that task lighting in offices be flexible and adaptable to each worker’s needs. “People are still individuals and one size lighting does not fit all,” he warned. ”



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