Way back in time, even before we were strolling around on two legs, when we were the very earliest form of life, our very being was controlled by the rhythm of the Sun and the Moon – light and dark. Throughout our evolution we have lived outside and our activity has been dictated by the lighting changes of night and day.
Then, all of a sudden we humans discovered how to create artificial light to lengthen our days and shorten our nights in a bid to make us more productive. Cities now have lights on throughout the night and we work in offices with bright lights and reflective glass through the day with no recognition of the subtle changes in natural light and how it affects us.
Many studies have been conducted that show how light affects sleep habits, our mood and mental functions. Adapting light levels, and more importantly, the quality of light to closely match the natural Circadian Rhythm offers huge benefits to our well-being.
The Circadian Rhythm is the reason you feel sleepy at night and awake during the day. It’s like an internal clock that runs in the background of consciousness that regulates when you should sleep and when you should be awake. It is the reason night workers find it hard to sleep during the day and hard to stay awake at night.
When it gets dark your eyes send a signal to your brain to release melatonin to help you fall asleep. Bright light exposure in the evening delays that signal which is why we hear repeated warnings about using tablets and smart phones in bed. Screens emit high levels of blue light which our circadian system is more sensitive to, the bluer the light the greater the stimulation to our circadian rhythms which will suppress the melatonin release and keep us more alert.
We are already seeing steps to counteract this built into our smart devices. In the evening your display will adopt a “night” mode that drops the level of blue light it emits and so allows your body to release melatonin, so you can sleep. NASA has also used these principles on the International Space Station to mimic a normal day and night cycle.
In lighting design we have always considered the visible “LUX” level of light. A lighting designer will talk about wall lamps being at 50% while ceiling pendants may be at 80% and a table lamp at 10%. What the designer is talking about here is simply how bright the light is, not about the quality of the light. Yet, at Seven integration we talk about quality all the time – the quality of sound produced by a speaker, not just what volume can it handle. The quality of an image on a screen, how well are colours represented rather than how bright can it shine. But when it comes to light, as an industry it has always just been about how bright do you want it – with the tiny exception of the early LED lamps which were rejected because they were too blue / cold / harsh when compared to the nice warm yellow of a tungsten lamp.
The Inuits of Northern Canada and Alaska have about 50 different words for “white”. There is no standard white light, it is made of all the different colours of the spectrum which we perceive as white, but some have a more yellow hue (warm white) and some have a bluer hue (cool white). We would call them all white, but the “temperature” is different.
Daylight offers a smooth consistent representation of the spectrum of light, as you can see from the graph below. If you compare this to a fluorescent lamp you can see how it is strong at certain wavelengths and weak in others. Trying to replicate the full spectrum of daylight is a challenge for the industry.
Ever wonder why we are generally happier in the Summer? Blue light is prevalent in the makeup of sunlight. During bright summer months our bodies absorb the blue light, which studies have shown strengthens connections within the brain that influence emotion and language. In the winter we absorb less blue light and our moods are conversely affected.
To combat the lack of blue light in the winter months research suggests adding blue light to the indoor environment to boost both mood and productivity. On the flip side, allowing our bodies to prepare for sleep by gradually adjusting the light to a yellow hue will begin the release of melatonin and bring on a great night’s sleep.
It’s not just mood and productivity that can be improved through human centred lighting. Using temperature changes in lighting systems can produce improvements in dental health, physical growth and development, alertness and academic achievement through better attendance at school. There are loads of research programs looking into the affects of lighting in medical environments and within our educational establishments.
Conversely, when light disrupts your circadian rhythm research shows links to diabetes, obesity and cancer so we need to learn to deliver the right light and the right time.
Fixed Programming – Where a lighting control system will be programmed to follow a set pattern of adjustment to the light temperature. This could be as simple as some programming that says if the time = x then the colour temperature should = y. This is what we currently see on our tablet and smart phone screens when “night mode” is activated.
Daylight Tracking – Using sensors to measure the current colour temperature of natural light and replicating that using artificial light indoors. This system could also be over-ridden so that when natural light drops to a certain level – once the sun has set perhaps, then it could revert to a fixed program state.
Wearables – By far the most exciting area of bio-adaptive lighting is the use of wearables to monitor our mood, health and physical state. Smart watches can already monitor heart rate, body temperature, sweat levels as well as many other hormone levels and emotional states. Soon these devices will be linked to our lighting system so when we need to sleep, the light is adjusted to produce melatonin and promote sleep. When we need to be awake blue light is introduced to our lighting scene and we feel alert.
As this area develops, there are experiments taking place looking at the effects of light emitted while we sleep and how it affects our circadian system. Seven days of exposure to pulses of blue light while we sleep shows a change in our circadian rhythm which could help people working shift patterns or suffering from jet lag – or more importantly preventing jet lag by preparing us in advance for the time zone change.
We are at the very infancy of this profound area of lighting control and the implications that it brings are only just being touched upon; but there are huge amounts of investment into it’s application in rehabilitation and education centres around the world along with hospitals and work places.
Manufacturers of the lomps as well as the control systems are all investing heavily – Lutron Electronics, the leader in smart lighting controls has recently signed an agreement to acquire Ketra a leader in “natural light solutions” which claim to seamlessly emulate daylight in interior spaces.
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