Understanding of the impact of light on human behaviour has advanced rapidly at the same time as lighting technology has undergone a major evolution with the advent of LED lighting. It is now possible to use the principles of human-centric lighting easily and cost-effectively in sensitive and care environments. At amBX we are working on cost-effective true circadian lighting for care environments. We call this bio-dynamic lighting as it combines LED lighting with sophisticated intelligent control that manages the lighting for the maximum comfort and well-being of patients, residents and staff.
The principle of bio-adaptive lighting is to provide artificial light controlled in such a way as to match the needs of human biological cycles, or circadian rhythms, in the most effective and appropriate way. It provides for improved health and wellbeing and supports aspects of human behaviour that benefit from spectrum-controlled lighting.
We are all governed to some degree by the circadian cycle (which is a little over 24 hours long) and light information from the environment resets the circadian clock every day to keep us in step. Light is the most powerful synchroniser of the human circadian clock, and the timing of light exposure during a day is responsible for how circadian rhythms are synchronised with the environment.
For example: Late-evening light exposure delays circadian rhythms, resulting in later sleep and wake times, and early-morning light exposure advances these circadian rhythms, resulting in earlier sleep and wake times.
It has long been recognised that there are significant benefits to healthcare from bio-adaptive lighting techniques. A study by The Center For Health Design in California found that by controlling the body’s circadian system, light impacts outcomes in healthcare settings by reducing depression among patients, decreasing length of stay in hospitals, improving sleep and circadian rhythm, lessening agitation among dementia patients, easing pain, and improving adjustment to night-shift work among staff.
As Mariana Figueiro, Professor and Light and Health Program Director, Lighting Research Center, Rensselaer Polytechnic Institute, says “High circadian stimulation during the daytime hours and low circadian stimulation in the evening is simply common sense.”
The use of as much natural daylight in care environments as possible is important but for people who spend a long time indoors under artificial light, bio-adaptive lighting should be a key consideration for any care environment.
The Power of colour
It’s not just about lighting cycles though, as colour plays an important part too. It’s known that certain blue light suppresses natural melatonin secretion in the human body and therefore acts as a type of fatigue-beater. One study from the Light Research Program at Thomas Jefferson University in Philadelphia found that blue light also strengthens and stimulates connections between areas of your brain that process emotion and language. This means that blue light may, in turn, help people to better handle emotional challenges and regulate mood over time.
Blue light is prevalent in sunlight, so your body absorbs the most during the summer and much less in the winter. Because of this, the researchers suggested that adding blue light to indoor atmospheres, as opposed to the standard yellow lights typically used, may help boost mood and productivity year-round, and especially during the winter.
The wavelength of visible light determines its colour and recent research has identified the impact from certain wavelengths. For example, a study by theSchool of Psychology in Adelaide showed that the shorter wavelengths of 470, 497, and 525 nm showed the greatest melatonin suppression from 65% to 81%.
It is important to manage certain wavelengths of the visible light spectrum at the right times in order to deliver effective bio-adaptive lighting.
Over the past decade, neuro-scientific research has uncovered the existence of a previously unknown non-visual optic pathway modulated by the substance melanopsin (which has a unique sensitivity to distinct parts of the visible light spectrum). Unlike other projections of the visual system, these pathways seem to play a minimal role in perception and processing of vision and image-formation; instead they have been found to be fundamentally responsible for entrainment and maintenance of circadian rhythms and other physiological functions.
In another study Figueiro found that, compared to remaining in darkness, exposure to red light in the middle of the afternoon significantly reduces power in the frequency ranges that have been associated with sleepiness. These results suggest that red light positively affects measures of alertness not only at night, but also during the day. Red light also seemed to be a more potent stimulus for modulating brain activities associated with daytime alertness than blue light, although they did not find any significant differences in measures of alertness after exposure to red and blue lights. This suggests that blue light, especially higher levels of blue light, could still increase alertness in the afternoon. It appears that melatonin suppression is not needed for light to have an impact on objective measures of alertness.
This doesn’t necessarily mean that we should all now have lots of different coloured lighting since blue is often in white light and having the ability to vary the actual colour spectrum of light is a critical factor in effective bio-adaptive lighting. Introducing colour changes and even tints at certain times of the day can be a highly effective way to deliver good bio-adaptive lighting.
Impact on People with Dementia
In a study entitled Spectral Sensitivity of the Circadian System, Mariana Figueiro showed that exposure to blue LED was shown to affect sleep quality and median body temperature peak in Alzheimer’s disease patients. Median body temperature peak was delayed by approximately two hours after exposure to blue LEDs compared with exposure to red LEDs and sleep quality was improved. This pilot study demonstrated that light, especially LED lights can be an important contribution to helping such patients regulate their circadian functions.
A further study in at a Sacramento Municipal Utility care home in the US, Innovative Lighting reported that a pilot installation showed very positive results from the use of bio-adaptive lighting. There was a reduction in falls by residents and improvements in sleeping through the night and a reduction in the use of psychotropic and sleep medications. They also recorded a reduction in resident behaviour episodes with one dementia resident showing a reduction of 71%.
The implications of lighting design for elderly care were highlighted by research in Singapore, which drew attention to the requirement to provide lighting that met the needs of ageing residents. As we age our eyesight changes dramatically and results in reduced visual acuity and colour discrimination and a slowing in the rate at which our eyes adapt to changing light levels and contrast. These changes can lead to disrupted circadian cycles and sleep patterns if not addressed by the lighting design in elderly care environments. It is therefore important than any lighting design for elderly care environments takes these basic needs into account.
A Lighting Guide for Dementia & Elderly Care Environments
One of the UK’s leading experts and lighting designers, Lorraine Calcott, is working with amBX and advising on how to deliver and manage bio-adaptive lighting effectively for dementia care environments. Lorraine specifies this type of full spectrum lighting as it works not only with our emotional responses to light but also on our biology to help re-set and maintain our bodies circadian rhythms.
“This process is critical for a healthy life, so using a circadian focused lighting product helps our body clocks to remain synchronised even when not out in natural daylight. This is particularly important for those who may struggle to get outside, such as people with dementia or Alzheimer’s, where an introduction of this technology can be life enhancing as well as reducing the need for support or medication. Of course, it also benefits their care givers who may work shift work to give 24-hour care and have trouble with a desynchronised sleep pattern that may possibly affect their mental and physical health. After all we are all not at our best when we don’t have a good night’s sleep. Getting outside in natural daylight for 30 minutes between 8am and 10am is the best medicine, however, when that opportunity is not an option, bio-adaptive lighting is a brilliant alternative to help you stay healthy.”
The typical lighting experience for supporting natural circadian rhythms in the elderly and Dementia sufferers follows these guidelines:
- White light exposure (with blue content) should be delivered at 480nm to give the greatest effect to the body for alertness and ultimately for sleep at the end of the day. Without the right ‘hit’ of white light during the morning for a long enough period then sleep ultimately suffers. Also restricting white light exposure later in the day will have the adverse effect
- The highest light levels and bluest light content should be delivered within the space between 8am and 10am. This is when the use of 480nm is most effective. This should continue no later than noon.
- From noon till 4pm the blue should begin to be faded out of the spectral content whilst maintaining as close as possible to a white light. The intensity would then drop to around 600 lux.
- From 4pm there should be no blue and the colour will be moving toward the 3000K, and below, end of the spectrum with intensity at around 500 lux.
- From 6pm the light colour should be in the red end of the spectrum (2200-1800K) and begin to introduce 620 and 670nm (red-orange) into the mix. Lighting intensity can drop a little but ample light level need to be maintained.
- From 10pm through the night the light settings should remain in the 6pm criteria setting except for areas such as nurses’ stations or staff rooms to ensure they don’t struggle to stay awake. Residents rooms however will need to be able to have complete darkness with no LED’s from emergency lighting. If night lights for safe passage to bathrooms and light in bathrooms are required, then they need to come on at low light levels of less than 10 lux and be of just the red end of the spectrum. This way the dark-adapted eye won’t be affected which may result in trips and falls.
The amBX Smart Core Circadian Lighting system is designed to deliver this in care environments of all sizes so the benefits of true human-centric lighting can be enjoyed by residents and staff, both for new-build and refits of existing buildings.