There is a tendency for recent publications and reports on healthy buildings to focus predominately on air quality.
It’s almost as if Indoor Air Quality (IAQ) particularly is sucking the oxygen out of the room! Perhaps we should look more at the topic of light and on how many levels this is critical to our health and understanding of how buildings can best enhance and support us.
Natural light is the most sought-after feature that employees want in the workplace
Light: the feature we all want
The UK Green Building Council recently stated that natural light is the most sought-after feature that employees want in the workplace. But an understanding of light can go so much further than this, as it integrally affects our health on numerous levels particularly our sleep and immune system. Specialist areas such as biophilia – our innate connection to nature – and circadian rhythms – our body clock – need also to be considered here in this discussion.
Ultimately working with a better understanding of light should enable our health by bringing us closer to the natural world, elevating our mood and supporting our bodily functions.
We should probably start with one of the most recognised health centric building standards – WELL. This involves a large section on light and can be quite specialist with technical engineering calculations. An overview of the light module however looks at the importance of strategies taking into account where people are working and giving people control over their environment and places that they work – which necessitates flexibility with lighting structure.
A recent report from Delos on burnout and design highlighted the real importance that people perceive in having control over where they work and being able to move around. There is also specific reference in the Mind module of WELL to restorative spaces and the attendant need for the dimming of electrical lighting and shading here.
Finally, the promotion of adequate and design-led lighting with views, windows and skylights were possible is promoted in areas such as hallways and staircases – previously sterile and often neglected parts of buildings!
Biophilia: more than just plants
As well as more design and health centric metrics, movements such as biophilia have a place in this discussion. Put simply biophilia is man’s natural affinity to nature. This is a bit more than just plants and wooden floorboards and Terrapin Bright Green’s paper “14 Patterns of Biophilic Design” is very helpful in categorising the different ways in which nature and design interact.
As far as light goes this can mean looking at light conditions and techniques that encourage sensory patterns or atmospheric qualities or savanna like environments with unobstructed views or themes of refuge. Even artificial elements of nature and light have been proven to reduce stress! And plenty of research validates enhanced performance and learning functions associated with biophilic strategies. Oliver Heath’s “Biophilic Design Guide” reports that within schools optimising daylight can increase the speed of learning by 20-26%.
Circle of light
Another growing area is that of circadian lighting. To understand this you need to appreciate that our biology is set up to work in partnership with the sun and the daily fluctuations in our bodies are called circadian rhythms. We already talk of course about our body clock and the science shows this affects our sleep, body temperature, blood pressure, appetite and mood.
Almost 50% of our genes are under circadian control
Even some of the most basic and earliest life forms on this planet – Cynobacteria – have this internal clock aligned with light and dark. And our eyes are important to our internal clock. In 2002, Retinal Ganglion cells were discovered behind the eyes as the body’s way to perceive external time. In Linda Geddes’ excellent book Chasing the Sun she cites numerous examples of circadian disruption that are serious to health caused by not enough natural light, nightshift work and the wrong colour of electric light. Almost 50% of our genes are under circadian control including ones linked with all the major illnesses like cancer, obesity and Alzheimer’s disease.
While UK Employers have a duty to provide lighting that is safe and not a health risk this does not currently look at the effects on our circadian systems. (Levels of illuminance of 200 lux in offices and 100 lux in factories are simply recommended). However why is it then that top class athletes, NASA and the US Navy all apply detailed circadian biology to their understanding of performance?
In fact there may be even more non-visual health factors associated with natural light – various studies showing a links with alertness and correlations of higher blood pressure and greater instances of Multiple Sclerosis with less light exposure.
It is encouraging then at least to hear of examples of hospitals looking at the benefits of circadian lighting – with the Royal Free Hospital in London installing it in their A & E department and the Glostrup Hospital in Copenhagen using it in their stroke rehabilitation ward. And with the lighting market there are now a multitude of LED lighting systems changing their colour temperature and illumination which are variously referred to as circadian, human- centric or biodynamic.
New WELL Metric for Light
As far as WELL is concerned it has in fact introduced a new metric for light known as Equivalent Melanopic Light (EML) which measures light at the vertical level and is a way to look at charting circadian rhythms. There is a lot of focus on morning light levels here and although research is ongoing electric light can satisfy EML levels.
Most lighting experts will always push for daylight rather than artificial light. Might there be a danger that advanced lighting systems become replacements for real windows? It seems people will often demand properly day-lit areas, yet the shortcomings of extreme temperatures or sound are always more immediately felt.
We can still work in bright light but won’t know this has affected our sleep necessarily until the next day.
And while there are big governmental pushes to boost air quality with emissions reductions and GLA recommendations for natural ventilation, we must ask why we are not seeing the same push for better daylight! (Having said that, there groups in New York demanding rights to better sunlight around towering skyscrapers).
In the end, to best maximise natural light exposure proper controls and zoning need to be incorporated between natural and artificial light using sensors. Before that even though, spaces should be designed that have whole different environments within them to allow people to choose where to be depending on the time of day, how they feel and what they are working on. Outdoor space really needs to be utilised here. WELL has been a good starting point for getting people to work in a variety of places.
Meanwhile research continues on what is termed “colour temperature” – a range of colour measured in Kelvin. This ranges from household light, early sunrise and candlelight to warm noon daylight to cool light. There is now an implicit understanding that people need such different types of light during the day to better attune to different tasks such as socialising and relaxing, collaborating and meeting and individual working.
As can be seen there are various considerations involved in the dialogue of incorporating light into buildings and their design. Let us hope that this becomes more mainstream as the links with better health become more widely publicised. The future should be bright!
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