Lights tuned to emit specific colors and brightnesses can support human capacity to perform specific activities better. That is the basis of the Human-Centric Lighting (HCL) industry, which has been growing at an increasing rate in recent years. If HCL can prove its abilities, it could soon be commonplace in our buildings and cities, creating a healthier, happier, and more productive society.

Two verticals lead the way for HCL; workplaces and healthcare. For businesses, HCL promises to make employees more productive, giving a overall boost to the entire enterprise. Investment decisions, however, require evidence, not just promises. While the scientific understanding is still evolving, a number of recent studies reveal that there is at least a psychological effect, if not a biological one, from lighting in the workplace.

In a survey of more than 1000 adults in the UK, a convincing 77% of respondents claimed they felt that lighting in the workplace affects their productivity. In the survey commissioned by LED Hut, 33% of respondents said that access to natural light is important, while 32% saying they would be happy to work under artificial light that is designed to aid productivity. The survey also found that many believe that lighting is important at home when creating a relaxed and calm atmosphere before going to bed in the evening, or energizing them in the morning.

In a Memoori survey, within our Future Workplace Report, we found that lighting had huge implecations for focus and concentration, which in turn influence productivity. The strength of respondents feeling towards lighting depended heavily on the current lighting in their office. Those who work under halogen / fluorescent tube lighting were the only group to say lighting reduced rather than increased their ability to concentrate, for example. The extensive survey analysis came to the clear conclusion that natural sunlight is the best light for productivity.

“It is perhaps unsurprising that abundant natural light had the biggest contrast, with more than six times as many respondents believing natural light aided concentration than those who didn’t,” the in-depth report on smart office design in the Internet of Things era stated. “Conditioned by evolution to respond to the tones and rhythms of sunlight, natural light is the ideal form of light to benefit employee concentration and therefore productivity.”

Millions of years of evolution have tuned humans to the natural rhythms of the sun. Scientists discovered non-visual photoreceptors in the eye that sense the color and intensity of light in order to direct the body’s circadian rhythm, our internal body clock. Blue-rich morning light awakens us, white midday light energizes us, the stronger red tones of late-afternoon and evening relax us, and darkness triggers the release of the hormone melatonin to help us sleep. The circadian rhythm also influences our mood, digestion, metabolism, and many other vital processes.

The emergence of widespread artificial light, about 100 years ago, changed everything. White light now shines late into the night as bulbs illuminate our buildings and streets. This facilitated our late-night culture but also confused our circadian system, energizing us in the evening when our evolutionary inclination should be to settle in for the night. This disrupts sleep but also mood, digestion, and so on, having a broad draining effect on our lives. In the workplace, traditional lighting keeps a constant “midday white” that pushes employees to focus beyond their natural capacity then disrupts their body systems, leading to a chronic productivity drain.

By incorporating HCL into their workplace, businesses are finding that they improve the overall health and wellbeing of workers, which in turn increases productivity both by raising output during working hours and reducing absenteeism. HCL mimics the natural rhythms of the sun to realign building occupants with the natural world. Just as we need earth’s unique combination of gases to breathe, we need a the natural daily pattern of light to operate optimally.

Office productivity is an obvious proving ground for the technology as competition drives businesses to squeeze more productivity out of their workforce but HCL has other applications. The healthcare sector has found that circadian lighting not only improves their worker’s productivity, which improves patient outcomes, but that HCL also helped patients heal.

“There is perhaps no environment more immediately suited to HCL than hospitals,” states lighting expert Mark Halper, in an article for LED Magazine. “It stands to reason that patients would rest better if bright lights didn’t keep them awake at night. Better still if tunable lights mimicked the shifting pattern of sunlight for a strong daytime semblance. To take all of that to a logical conclusion: Patients who rest and feel better surely must recover faster.”

Two nurses, Lone Moeslund and Leanne Langhorn, who work at the intensive care unit at Aarhus University Hospital in Aarhus, Denmark, convinced their hospital to employ HCL in their brain trauma ward. According to the nurses, the system, provided by Danish circadian and ergonomic lighting specialists at Chromaviso, is bringing about the desired results. Before HCL, patients would typically sleep “fitfully” and were disoriented upon awaking, often not knowing what time of day or night it was, but HCL appears to be changing that.

"It's really good for the patient," said Moeslund. "I believe that we've made a good circadian rhythm for them. It's light that's bright in the daytime and dark at nighttime. That must make a difference to them. I can't conclude that for certain yet, but I think we are giving them a better circadian rhythm. And if they get a better sleep - we don't know this yet, but we think they recover faster."

Lighting that helps people heal better and work more efficiently, can also be utilized by education to help teachers teach and students learn, or coaches coach and athletes train, or could even influence street lighting to help drivers drive better. The benefits this new type of lighting can bring to society are potentially huge. By getting human biology back on track with the sun’s rhythms through artificial light, HCL can balance the evolution of modern society against the demands of our natural biology.