The Edison era of light for light's sake is giving way to a new age. MARK HALPER reports on LED technology that can tune the body's circadian rhythm for better health and sleep.
Pretty much since the inception of artificial light, people have been using and experimenting with it to alter settings and set ambience, to provide calm, to stimulate. Even if illumination has been the main stock and trade of the lighting industry, human effects have always been somewhere in the mix.
As Bob Karlicek, the director of Rensselaer Polytechnic Institute's Center for Lighting Enabled Systems and Applications (LESA), noted, "We don't have the expression 'mood lighting' for nothing."
But in the last few decades, scientists have come to a firmer understanding of how the spectral content and intensity of light can alter biological processes. Many studies have shown a connection, for instance, between blue-rich white light and the suppression of the sleep-promoting hormone melatonin, leading to many warnings about using LED-lit gadgets and computer screens, or even general illumination LEDs, at night.
Conversely, recent research has shown that blue wavelengths can excite a pigment called melanopsin that resides in the eye's non-visual photoreceptors (known as intrinsically photosensitive retinal ganglion cells or ipRGCs) and sends stimulating signals to the body's master clock that resides in the brain.
With such impressive science, it seems that lighting is on the cusp of a new human-centric era, in which we can use the same light we use for general illumination to encourage physiological effects such as sleep and stimulation. White light with a strong red spectral makeup might help us sleep. Blue light might help us stay alert and learn. And so on.
Learn more about human-centric lighting and how light promotes health and productivity at the 2017 Lighting for Health and Wellbeing conference July 27 in Newport Beach, CA:lightingforhealthandwellbeing.com
What makes the possibility all the more likely is that LEDs lend themselves to delivery of different wavelengths. "The LED allows us to be a little bit more precise than incandescent because you can tune the spectrum," noted Mariana Figueiro, acting director of Rensselaer's Lighting Research Center (LRC), a sister research center to Karlicek's LESA. "You can change the spectrum over the course of the day."
FIG. 1. Nurses Leanne Langhorn (l) and Lone Moeslund (r) pushed for a circadian lighting system at the brain trauma ward at Aarhus University Hospital in Denmark to help patients recover faster. The technology seems to be working, as patients are resting better and are less stressed, among other benefits.
But exactly how the concepts proven in laboratory studies might work across homes, workplaces, offices, factories, hospitals, care homes, schools, and the like is something that is still in its early days and largely unproven on a broad operational level.
With this issue, LEDs Magazine starts a two-part feature looking at the possibilities and obstacles for human-centric lighting (HCL). First, we examine one sector that is ramping up its deployment - healthcare. A grassroots movement is building, pushed by nurses and staff at hospitals and care homes imbued with the notion that lighting can balance circadian rhythms, help patients sleep and engage in a healthy pattern, and thus facilitate healing. We also look at the literal heights of circadian lighting - an experiment on the $150 billion International Space Station, which is sure to capture the imagination.
In our next issue we will round up some attempts to prove HCL's effect in the workplace, where some proponents go so far as to link it to productivity. Figueiro's LRC group, for instance, is doing some interesting work with the offices at the US General Services Administration. Although she is the first to say that it is very difficult to prove a direct link with productivity, she sees tremendous potential for human benefits. Karlicek's LESA has some ambitious ideas of how to engineer personally tailored healthy lighting systems. And we will look at impediments. Peter Thorns, part of the Light for Life group at industry association LightingEurope, believes that the industry needs standards to overcome the obstacles.
FIG. 2. A patient in the Aarhus University Hospital trauma center is bathed in a daylight mode via the Chromaviso lighting system that offers programmed modes tuned to circadian rhythms.
We hope you find these reports edifying, and we welcome your feedback. We anticipate that you might not concur with everything that we report here. After all, the industry itself lacks agreement. (For examples, see some interesting viewpoints that LEDs Magazine has published: http://bit.ly/1l9Xc2d and http://bit.ly/2aAtoeE.) Figueiro, for instance, sees a role for red light as a stimulant that others dispute. And the industry is split on the need for regulation. The HCL movement is not without controversy. It is, after all, only human.
HCL's first frontier: Hospitals
There is perhaps no environment more immediately suited to HCL than hospitals. It stands to reason that patients would rest better if bright lights didn't keep them awake at night. And that they would simply feel better if poorly-lit wards and rooms didn't induce a general fogginess. 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.
FIG. 3. Circadian lighting developed by Chromaviso changes over each 24-hour period to provide dynamic and functional illumination suited to various tasks and moods in the Aabenraa Hospital psychiatric ward.
Just ask nurses Lone Moeslund and Leanne Langhorn in the intensive care unit at Aarhus University Hospital in Aarhus, Denmark (Fig. 1). Moeslund and Langhorn pushed for and received a circadian lighting system that modulates light frequencies and levels such that patients receive gradually brighter and more blue-enriched light from the morning into the afternoon. Later in the day, the intensity drops and the spectrum veers towards amber - mimicking the natural pattern of daylight. For example, Fig. 2 shows a daylight scheme provided with uplight in an Aarhus patient room.
Equally important, the lights turn off at night, providing darkness that helps maintain sleep and keep the patients' circadian rhythm in balance - a key element in recovery.
Moeslund and Langhorn look after patients who have suffered brain traumas from car accidents, falls, strokes, aneurysms, and other conditions. According to the two nurses, the system, provided by Danish circadian and ergonomic lighting specialists at Chromaviso, appears to be having the desired effect.
Prior to installing the Chromaviso lighting and control system, patients would typically sleep fitfully and were disoriented, often not knowing what time of day or night it was, Moeslund noted.
But that is now changing. Moeslund recalls how one patient, benefitting from the Chromaviso lighting system, slept so soundly that the staff could not wake him at 6 a.m. for a scheduled check. "But after the lights started slowly turning on at 6:30, he woke up," she recalled (the Chromaviso system includes infrared cameras that allow staff to switch off room lights at night and monitor the patients visually from outside). They have also noted greater levels of cooperation and reduced agitation from the patients.
Moeslund and Langhorn are the first to acknowledge that anecdotes like that do not firmly prove that circadian lighting assists the healing process. But it sure feels right.
"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."
The staff is benefitting, too; night shift workers are reporting that they are sleeping better during their daytime slumber hours.
Moeslund and Langhorn are now making clinical observations and gathering evidence that they hope leads to solid conclusions. The trauma unit deployment, which started in 2011 as a small implementation in a room with 3 beds, expanded in 2014 to cover 12 beds in total.
Research nurse Langhorn, a PhD specializing in rehabilitation medicine, brain traumas, and neurosurgery, is leading the trauma study at Aarhus. She grew interested in the circadian idea for practical reasons, among others. "The patients were a challenge for us," she said. "They woke and they were not orientated and they were agitated, and I thought instead of giving them medicine it would be better to look at their surroundings, to see if we could do anything with the surroundings to calm the patients."
The unit is applying other environmental techniques as well, such as therapeutic music and digital sign boards that tell the patients where they are. But lighting is the cornerstone of those efforts. Langhorn plans to study a total of 21 brain trauma patients, and to reach her conclusions next year.
World's biggest study
The Aarhus intensive care study is part of a broader £1.3 million ($1.7 billion) project to be completed by next year that also includes 73 patients suffering from bleeding on the brain at Rigshospitalet Glostrup hospital in Copenhagen, and which, like Aarhus, is using circadian lighting from Aarhus-based Chromaviso.
Torben Skov Hansen, Chromaviso's head of innovation and quality assurance, said the combined Aarhus and Rigshospitalet initiative is the largest and most extensive circadian lighting research project to date of human patients in somatic (non-psychiatric) hospitals. In both hospitals, researchers and clinicians are measuring a sweep of different reactions to the lighting, including blood, circadian biomarkers, sleep quality, anxiety, and cognitive performance, among others. One of the key areas of study is circadian entrainment, which is a measure of how strongly the body clock is tuned to natural day/night patterns.
"The light itself is not healing, but it improves what you would expect as basic human functions," Skov Hansen said. "It's like walking - entrainment to day and night is one of the basic functions we have. We need sleep each and every night, and we need it in constant occurrence. And it is light that is the main entraining factor. The main source to synchronization is the light and the daily pattern of light and darkness."
Chromaviso has many other circadian lighting installations in the healthcare sector including additional intensive care units as well as in psychatric hospitals (Fig. 3), memory centers, and elderly care homes across Scandinavia. Its technology helps stimulate dementia patients and treat psychiatric disorders like depression, schizophrenia, bipolar disorder, eating disorders, and SAD (seasonal affective disorder, also known as winter depression and common in the Nordic region).
FIG. 4. Hospital employees in Karlstad, Sweden are able to modify lighting modes for flexible patient care - for example, programming the right light level and spectrum to enable an exam without disrupting the patient's natural sleep and wake cycles.
"Lighting can catalyze a good sleep/wake performance, which leads to better cognitive performance, better immune systems, and social motivation, and that leads ultimately to more efficient take-up of what the medicine and the clinical treatment is aimed to give," said Skov Hansen. Citing a Harvard University sleep and mental health roundup, he noted that 50-80% of psychiatric patients suffer from a circadian disorder, which undermines the effectiveness of their medicines and other treatments.
Blue days, dark nights
Lighting-based circadian entrainment works in many ways. Much of it is related to coordinating artificial light's intensity and spectral makeup (the varying blends of blue, red, green, and other wavelengths that combine to form different color temperatures of white light) throughout the day to a pattern that follows the sun's time-honored daily routine of a spring-like day. For millions of years, the sun has delivered an increasingly blue-rich icy white color through its peak hours of brightness. It shifts toward warmer reds and ambers as it moves toward sunset.
Blue enriched light stimulates the circadian rhythm, also known as the body clock. Among the reasons: Blue wavelengths, more than any other frequency, excite those aforementioned non-visual photoreceptors called ipRGCs. Specifically, they stimulate a protein in the ipRGCs called melanopsin, which sends signals to a portion of the brain called the suprachiasmatic nucleus (SCN) that acts as the body's master clock (the cones and rods of the eye's visual system also communicate with the SCN).
Circadian lighting systems administer light that follows the gradual shift from invigorating, intense blue-rich white down to relaxing reds and oranges in the evening. The red and orange facilitate the flow of the sleep-promoting hormone melatonin. Too intense blue-rich light in the evening and night would disturb the production cycle of melatonin and thereby would disturb sleep.
On the Kelvin (K) temperature scale, the cool blue-rich whites counterintuitively have higher numbers, measuring around 5000K, 6000K, or more. Warm, reddish whites have lower numbers. Conventional incandescent lamps, considered warm, are associated with 2700K or lower.
FIG. 5. At the St. Augustinus Memory Center in Neuss, Germany, wireless circadian lighting products and controls developed by Osram for the sleeping quarters deliver cooler-white light during active, daylight periods (top) and a more restful amber glow late in the day (bottom).
LED light sources can be tuned to those temperatures by combining desired amounts of specific wavelengths far more accurately than any other light source has ever allowed, using sophisticated controls. Many LED circadian lighting experts like Skov Hansen maintain that a typical LED lamp at 2700K produces more blue wavelength than a 2700K incandescent, and is therefore more disturbing to the body clock during the evening. Thus, some LED systems strip out more blue and deliver temperatures lower than 2700K during those hours.
In the Chromaviso system, lights eventually reduce down to amber white in a location where they are needed at night - such as, say, a corridor. They switch off altogether in the sleeping quarters. Circadian experts tend to agree that regularly occurring darkness is as critical to resetting the 24-hour body clock as is properly tuned daytime light. As Skov Hansen noted, "The cyclical motion is primarily entrained by the daily presence and absence of light."
Chromaviso's projects across Scandinavia, which include intuitive control systems for healthcare personnel (Fig. 4), reflect a growing movement among care facilities around the world to deploy and study lighting that stimulates the human circadian rhythm and aids the healing process.
During Strategies in Light Europe, the program will feature a session on the response of the human body to light, with speakers from Osram, Humanscale Corp, and Philips Research delivering details on what constitutes human-centric lighting and how to design it, as well as what the right light at the right time can do for the commercial workspace. View the full program and register.
Benefiting dementia patients
The St. Augustinus Memory Center in Neuss, Germany, for example, is investigating whether varying the light spectrum and intensity can help normalize circadian rhythm and improve the wellbeing of the center's dementia patients.
Chief physician Dr. Ulrich Sprick began trialing light and control technology from lighting giant Osram last December. After several months in which Dr. Sprick and his staff familiarized themselves with the system, he was preparing by September to launch a formal study of the effects of the variable lighting on circadian rhythm.
St. Augustinus, also known as AMZ, is experimenting with 28 recessed ceiling lights and about 20 wall lights in the patients' common living and eating area wired to a DALI control system, and with 26 ceiling lights in the sleeping areas controlled wirelessly, according to Andreas Pickelein, Osram's senior project manager (Fig. 5). By using two different controls, Osram hopes to prove that circadian lighting could function in existing healthcare facilities where wireless controls would be more practical than rewiring would be, as well as in new facilities, where hard-wiring the controls would make more sense because no rewiring would be necessary.
While the circadian lighting will draw on preset, central controlled patterns, nurses equipped with tablet computers will be able to modify the settings. In some instances, the staff will ask patients to choose the light settings that they prefer.
Pickelein is hopeful that both systems at St. Augustinus will have the desired effect.
"A very important question when you're talking about circadian lighting is 'How can I design the lighting to activate the melanopic receptor (the ipRGC) in the retina?'" noted Pickelein. By this time next year, Sprick and his team at St. Augustinus should know whether they have succeeded.
A common theme in Chromaviso's Aarhus/Rigshospitalet and Osram's St. Augustinus project is that both include a heavy dose of stimulating the ipRGC to activate melanopsin and the suppression of melatonin during the day.
The melanopsin trail winds to London
The same is true at the dementia ward at St. Mary's Hospital in London, where 56 LED downlights and a wireless control system from UK-based PhotonStar is calibrated to deliver melanopic light levels intended to keep patients' circadian rhythms in order.
The melanopic and non-visual quotient gets to the heart of what defines a circadian lighting system, rather than the visual element of lighting, noted PhotonStar group marketing and business development director Fenella Frost.
"Circadian lighting is lighting which is able to change from a high level of melanopic light in the daytime while also meeting visual needs, and has no melanopic lux at nighttime," noted Frost.
She cited a 2014 study by 14 academic experts entitled "Measuring and using light in the melanopsin age," which described the correlation between different light wavelengths and melanopsin activation in the non-visual photoreceptor.
The study called for new ways of measuring melanopic effect. While measurements have not yet been standardized into firm guidelines, companies like PhotonStar and its rivals Chromaviso, Osram, Philips, and many others are applying their own technologies and measurements.
"The basics are, we know how your eye responds to light - that bit is proven," Frost said. "We know there is a cycle, that you need more in the day and less at night. Within that, doing something is better than doing nothing. Fixed white light is terrible. Doing anything that's more like nature has got to be good."
Grassroots appeal, and how to fund it
That message has a grassroots appeal: It was the nurses at St. Mary's, like at Aarhus, who saw the common sense of better lighting and who pushed for it (such rank-and-file, staff-driven advocacy is on the rise at other hospitals; see our recap of LuxLive and Strategies in Light Europe, at which these types of HCL efforts were under discussion).
But with circadian lighting still in its early days, and in need of more case studies and indisputably positive results, St. Mary's justified the expenditure based on the tried-and-true LED benefit of energy savings.
"The clinical staff wanted circadian lighting, but the signoff, funding wise, had to be based on energy savings," said Frost.
While the system would have been less expensive without a circadian feature (some circadian systems come at a huge premium), Frost said the payback will still be less than three years, which is within the parameters of the UK's National Health Service (NHS), to which St. Mary's belongs.
"By taking this action, they gave the patients greater benefit, and the NHS will be saving money over a three-year period," said Frost. "The cost of the installation was very low, because there were no new wires or product relocation or anything," She declined to reveal how much PhotonStar charged for the system, although she said that it saved the NHS money and downtime by installing wireless controls by way of the PhotonStar Halcyon system.
After a short hiatus, St. Mary's reopened the ward in the spring. The upshot is that patients now have a "sunnier" indoor environment that should help tune their body clocks and induce better rest.
"What would you get if you were in the south of France? We're going to deliver what nature delivers," said Frost, echoing a common refrain among circadian lighting proponents.
Or as Chromaviso's Skov Hansen noted: "We try to mimic what on an evolutionary scale humans have long been exposed to. And on an evolutionary scale, that's the sun, the moon, and then, some quarter of a million years ago or something like that, humans became masters of fire as well."
Sun, moon, darkness, and the warm glow of fire. It's the rhythm of life, and increasingly, of light. Artificial light. And health.
In our next issue, LEDs Magazine will look at circadian lighting in the workplace, which has huge potential but where there are more obstacles than in the healthcare sector.
MARK HALPERis a contributing editor with LEDs Magazine (firstname.lastname@example.org).
LED circadian lighting system will soar to the Space Station
Astronauts on the International Space Station are as physically fit as people come. That includes healthy sleeping patterns. On Earth they tend to slumber 7 or 8 hours a day. But thrust them into orbit some 250 miles high where the sun rises and sets every 90 minutes, and their circadian rhythm goes haywire. That's not good.
"The biggest problem identified is loss of sleep and sleep quality," noted George "Bud" Brainard, the director of the Light Research Program at Thomas Jefferson University, a medical science research institution in Philadelphia, pointing out that the average sleep time on the Space Station drops to around 6 hours.
"That might not sound like a lot, because many of us shave an hour or two here or there," Brainard said. "But when you're losing an hour or two day after day, week after week, month after month, that's called 'chronic partial sleep deprivation.' And when you're working in a very high-risk, high-tech environment, mistakes can really have life-threatening consequences."
The International Space Station will become a "living lab" for a novel human-centric lighting project to test how circadian lighting may affect astronauts' routines and sleep cycles.
What better place, then, to set up a living laboratory of LED-based circadian lighting than the Space Station? That's exactly what Brainard and his colleagues from Harvard University and NASA's Johnson Space Center are doing.
They've developed a system of tunable LED lights that have three basic settings: general vision for most of the day, circadian phase shifting/acute alerting when required, and a pre-sleep setting to induce restfulness.
The system is set to start arriving at the Space Station as early as October, with the first installment earmarked for four separate astronaut sleeping quarters. Eventually, it will expand beyond the individual chambers and into common areas, replacing what is now a fluorescent system with a few too many failed tubes and dim spots.
According to Brainard, NASA had originally planned to upgrade from fluorescents to an LED system that offered standard on/off settings, but not much more. Scientists then pointed out that "they had a perfect opportunity to have a spectrally dynamic lighting system that potentially improves circadian regulation and sleep in astronauts," he said.
So the approximately 240-ft-long, 360-ft-wide, and 60-ft-tall structure, believed to be the most expensive thing ever built at a cost of somewhere around $120-$150 billion, will soon start to provide some operational insights into whether circadian lighting theories actually work.
"The hypothesis that's being tested is whether these lights will offset some of the circadian and sleep problems astronauts have during space travel," said Brainard, who is also a member of Rensselaer Polytechnic Institute's Light Enabled Systems & Applications (LESA) research center. "There are many times they have to switch their work schedules. If there's a docking of a supply rocket, they may have to flip their work schedule 180 degrees, in which case they've got to re-adapt their circadian system."
In those instances, astronauts would use the circadian phase shifting/acute alerting setting, which in theory would take several days to reset their body clocks. The astronauts might use the same setting at night if they wanted to prepare for a task the next day, or they might also use it for a short time after waking for a boost.
The ISS crew will operate under a new LED-based circadian lighting system with three settings for various routines: general vision, circadian phase shifting/acute alerting, and a pre-sleep setting to induce restfulness.
Conversely, they might apply the pre-sleep mode, skewed toward a mix of warm color temperatures, before going to bed.
"Do we know it's going to work?" Brainard posited. "No. This is going to be very much a set of anecdotal studies in the early days. Until the whole station is retrofitted, they're going to be getting a blend of solid-state and fluorescent lighting, including they have the opportunity to look out of portholes at sunrises and sunsets and the planet."
With something as promising - but still unproven - as circadian lighting, you have to start somewhere to prove it in the workplace. Even if it's 250 miles up in the sky.