Everyone is talking about Circadian Lighting, but what is "True Circadian Lighting"?
Human-centric, bio-dynamic, bio-adaptive, chronobiologic, biophilic, circadian, melanopic, it's acknowledged that there's no universally agreed wording – therefore, we will call it circadian lighting for continuity purposes.
There are a lot of people talking about circadian lighting at the moment; we have seen an increased focus on the 'healthy buildings' mantra, which encompasses lighting, ventilation, air quality, occupant analytics, contactless operations, etc. Circadian lighting clearly forms a big part of this conversation and is now gaining a higher uptake due to these changes in market attitudes. Commercial real estate owners need to upgrade their buildings to increase value and attract tenants. Many tenants have become accustomed to working from home; therefore, they need to be enticed back into the office and made to feel safe when they are there.
The other big driving force in the market at the moment is energy efficiency. Building stock has to become more energy-efficient; this is essential and necessary.
However, on the surface, these 2 forces appear to be opposed. Energy saving is the primary most important driver, but building services such as circadian lighting are often linked to higher energy usage due to increased brightness, and many systems incorporate non-visual radiant energy and operate at a higher intensity. But, in reality, the amount of energy used can be minimised greatly by designing lighting and controls for people instead of numbers - therefore, we can win at both occupant comfort and environmentally friendly solutions.
Data is the key; being able to track usage, automatically power down when an area is not in use and have insights easily accessible for building managers and facility managers to view and act upon is essential.
Why do we need Circadian Lighting?
CABA, a large US trade association, recently released a whitepaper about the "Benefits of Advanced Lighting Systems on the Human Experience". They state, today we face a problem; on average, over 90% of our time is spent indoors. Electric light is too dim to replicate daylight and too bright to be nighttime, so we're living in constant twilight. Our body ends up secreting too much melatonin during the day and not enough at night, reducing the quality of our sleep. Poor sleeping habits or not getting 8 hours of sleep can cause high blood pressure, diabetes, stroke and even heart failure. However, it also has a profound impact on our daily activities too; in general, we are more tired, have difficulty focusing, are cranky and don't feel like the best versions of ourselves.
Appropriately designed circadian lighting systems can help to alleviate some of these issues, receiving suitable lighting brightness, hue and saturation and ensuring lighting hits the eye at the right angles. This can be hugely beneficial in terms of productivity, concentration, mood and, over time, increases human health.
Personalised control of individual lighting is also important; being able to adjust your environment based on the task you are completing has been linked to increased productivity, but CABA has found it has also been linked to reduced sick days and reduced job turnover.
As we know, in many organisations, employees are the most expensive asset they have; therefore, prioritising their health and wellbeing also positively impacts the bottom line because recruitment costs will be reduced, employees will be happier and healthier; therefore, fewer sick days and higher productivity can be achieved. Circadian lighting alongside the other 'healthy building' services makes sense. Why wouldn't employers and building owners want to adopt it?
Our partner recently conducted their own research in conjunction with Newcastle University looking at the impact of circadian lighting on the elderly and people with dementia. The full report will be released soon.
At amBX, we have completed a couple of care home installations which have delivered some amazing results. Typically, residents who live in care homes spend a large proportion of their day indoors; therefore, it can become very easy for their body clock to get out of sync. You can watch our case study video of Heanor Park Care Home here.
What is "True Circadian Lighting"?
The report produced in conjunction with Newcastle University highlighted that it is clear melanopic lux and photopic lux (brightness) of light needs to be personalised / tailored to each individual, depending on their eyes, their environment, and their personal biological rhythms. They go on to state that lighting, therefore, needs to be tuneable both in spectrum and in overall irradiance. It is important to remember the amount of melanopic lux depends not only on the light spectrum and overall irradiance but also on the individual's eyes.
A recent study suggests that having regular daily exposure to light with a fixed amount of melanopic lux, for a sufficient duration each day, over a long period of time, is enough to ensure a good sleep/wake cycle and good sleep quality in older people (Figueiro et al., 2020). Having a sleep/wake cycle that is in sync can have a hugely positive impact on individuals' health, and we found from our installation at Heanor Park that it also dramatically decreased the number of falls a care home would usually experience. This can be linked to overall brightness being increased during the day; therefore, residents can see where they are going better but also feel more alert because they have had a better sleep; therefore, mistakes and trips are reduced.
The report also discussed the trade-off between providing stimulation to the non-visual pathway to optimise circadian rhythms and guarding against damage to the eye. Short-wavelength light at high doses damages the lens and the retina (the "blue light hazard"). Yet, short-wavelength light is also the most effective in activating melanopsin, the photopigment in the intrinsically photosensitive retinal ganglion cells (ipRGCs) that feed into the non-visual pathway that governs the sleep/wake cycle and other biological rhythms.
It is important to consult an experienced lighting designer and have a credible research organisation as a partner when delivering circadian lighting in any environment but especially in a sensitive environment such as a care home.
Therefore, the difference between many of the circadian lighting solutions talked about within the industry and "true circadian systems" are the fact that they are personalised, not just tuneable white but completely dynamic in terms of saturation, brightness and hue and the lighting hardware is also designed so that the lighting hits the eye at the right angle to trigger the retinal ganglion cells and have the most effective results. Tasks and activities also need to be considered; the lighting needs to adapt to individuals, rooms and changes in events. Darkness is also a key requirement, it's easy to only think about lighting and the lit space, but it is essential that residents have darkness at night, "we do not want to introduce control devices with flashing LED indicator lights — especially white, blue, or green. We do, however, want the occupant to be able to see where the local keypad is, and so keypads should have amber-coloured indicator lights if possible and/or indicator lights that adjust to a dim level when the room is dark" (CABA 2021).