Circadian lighting plays a special role in facilities management as long-term care homes and schools increasingly look to enhance wellbeing among seniors and children with Autism Spectrum Disorder (ASD) who all rely on daily routines.
In The Power of Routine, the Illuminating Engineering Society’s (IES) first ever virtual webinar, Connie Samla, a lighting specialist with the Sacramento Municipal Utility District’s (SMUD) Energy Education and Technology Center, discussed how correlated colour temperature changes throughout the day can reinforce routines and ease transitions between activities. She also highlighted recent commercial and residential research projects that support this finding.
A “primary synchronizer”
Since light is a “primary synchronizer” of humans’ circadian rhythms—a natural process that regulates the sleep-wake cycle and is tied to a person’s 24-hour body clock—using light in human-centric design can have profound effects on people’s day-to-day lives. It can jumpstart the human system to stay awake or be used to relax and fall asleep. Hormones control much of this internal rhythm.
As Samla pointed out, the deepest sleep happens at 2 a.m., with sleep hormone melatonin secreted at night and stopping sometime in the morning. Serotonin sets in as the day hormone, with alertness at its height by 10 a.m.—“a good time for meetings.” The idea is that these two hormones coincide on a regular basis to optimize one’s best self.
“Light changes colour throughout the day—we have beautiful sunsets and sunrises—but then during the day, it’s very blue, and it does change colour temperature, so why not take that inside?” she asked. “We don’t have to be under a stagnant colour of light all day long.”
The advancement of LEDs has helped to achieve this feat, specifically tunable white LED lighting fixtures that are capable of adjusting colour temperature and intensity, from very warm to very cool.
According to SMUD, the appearance of light sources is measured and described using a metric called Correlated Colour Temperature (CCT). This system uses degrees in Kelvin as the units of measure. Lights that appear warmer have lower CCTs (i.e. 2700 K). Cooler lights have higher CCTs. Warmer tones are recommended in the evening and higher CCTs for the morning.
Improving seniors’ daily lives
Pilot studies beginning in 2015 exemplify the power of tunable white light in long-term care facilities. One such project involved residents in their eighties at the ACC Care Centre in California, many of whom had severe forms of dementia and were wheelchair bound. A key to circadian lighting is that it be installed where people spend the most time. The project involved relighting corridors and resident rooms using automatic controls for day-to-day changes, as well as the nurses’ station which operated on manual controls.
Lighting was programmed for daylight (5000 K to 6000 K) in the morning, white light (4000 K) in the afternoon, and dimmed warm light in the evening (2700 K) to the point where the areas were only 20 per cent lit.
The lighting routines, despite not always attaining the optimum circadian stimulus or melanopic response, proved to be quite helpful. They reinforced wake-up and bed times and offered a sense of stability. For instance, when seniors needed to use the washroom in the middle of the night, amber night lights tied to motion sensors turned on automatically beneath the bed and also in the washroom.
“In the bathrooms, since they have handrails anyway, why not incorporate LEDs dimmed low on a motion sensor into those handrails,” said Samla. “It didn’t take up any more space, it was clean and it gave them enough light to see what they needed to do.”
In the past, residents would lose their night vision upon turning on a washroom light and have trouble making their way back to bed. Most falls occur at this time because residents are no longer “dark adapted” and can no longer see furniture in the middle of the room. The researchers found the use of low-level amber lighting does not affect night vision.
As the light slowly increased for wake-up time, consequently, residents were more alert and awake during the day and slept better and longer throughout the night—a time when the body heals itself. There was also a reduction in sleep and dementia medication. Samla pointed to one resident who, after six to eight months, was taken off her dementia medication completely. The lighting was “helping her body to recuperate and restore itself night after night after night.”
“And there was a reduction in behaviours—of yelling, agitation, crying—and what that did was it really had a ripple effect,” said Samla. “Once a resident is yelling, all the residents can hear it, and it affects them,” she said. “And, of course, it made the nurse’s job a little easier because they weren’t spending as much time with a certain resident.”
Circadian lighting for the spectrum
Children with special needs also depend on daily routines. Beginning with an elementary school in 2018, researchers installed and tested tunable white LED lighting systems in three classrooms, since the school board was already looking to revamp its lighting fixtures across the board. Two classrooms were used for teaching students with ASD, while a fifth grade classroom taught students without ASD.
Original lighting averaged 570 to 910 lux at desk level, compared to new lighting that averaged 300 lux at desk level—much less stimulating and easier on the eyes.
Twenty-four 2 x 4 recessed fluorescent luminaires were switched up for twelve 2 x 2 recessed tunable white LED luminaires that moved from 2700 to 6500 K. The teacher could also use a touchpad controller to manage the light for calming students. It was discovered that the lighting system offered an improved working and learning environment. The dimming colour tuning offered an effective cue to get students’ attention, while instantly changing the whole dynamic of the room.
Children with ASD often suffer from sensory overload, Samla added. Lights bring too much glare, sounds bring too much noise, and some can’t stand the touch of water. Meltdowns often ensue. Teachers being able to dim the lights to a warm colour helped reduce those meltdowns and allowed children to transition into the daily activities.
Newest study called Lighting for the Spectrum
Lighting for the Spectrum, a more recent study completed last year, saw the installation of these lighting systems in the homes of students with ASD. After all, circadian rhythms are 24-hour cycles, not just school-hour cycles. Behavioural specialists at the UC Davis Mind Institute were on hand to clarify best practices and work alongside parents.
The primary goals of the project were to help children and their parents or guardians sleep better, reinforce routines and transitions, avoid exposure to blue-white light at night and provide lighting for safe nighttime navigation. Over the course of 29 weeks to six months, it included 33 families with children aged five to 10 years old, living in both apartments and large single-family homes.
Researchers discovered that the families used either too much light or no light at all. There were various dimmers and daylight colour light bulbs in the child’s room and bathroom. Meanwhile, since many children with ASD are sensitive to different smells, some parents would place colour-changing aromatherapy diffusers next to their child’s bed, exposing them to white, blue and green light changes throughout the night. Exposed light bulbs in fans and other fixtures also brought too much glare.
Replacing these items was a circadian routine, including time-based light with customizable scheduling. The temperature would range from 6500 to 6600 K at wake up and slowly dim down to 2200 K for night-time navigation, as many children were scared of the dark, which caused bed-wetting at night.
Equipment, including tunable light bulbs, fixtures and light-strips, and wireless dimmers, switches and motion sensors, all created various types of routines catering to different children.
For one child where bedtime was often a battle, the lighting was programmed to turn a warm amber colour half an hour before bed, in a spot where he would typically play. Once the lighting cued, he would get ready for bed, and eventually started falling asleep within five minutes. In another home, where dinner was prepared under fluorescent lighting in the kitchen, the child would often isolate himself in his bedroom to avoid glare.
“Relighting the kitchen allowed everyone in the family to dim the lighting enough to see what they were cooking, without it being harsh on the child’s eyes. They were able to become a family again.”
Overall, families in the study reported significant improvements in daily routines, behaviours and activities, including sleep, with 77 per cent of respondents saying the lighting system was “high impact” to “life changing.” The time it took children to go to bed trended downward and stayed that way, albeit for some rough patches here and there.
For Samla, in the beginning, it was “alarming to see how anxious the children were all the time.”
“Many were non-verbal, but they were very audible; so they’d be making noises to express themselves and some would express themselves physically,” she noted. “And they’re young, so they’re just learning how to do that.”