Effects of Biodynamic Lighting
Another study into tuneable lighting in educational premises by Russian outfit Lighting Technologies has shown positive results when compared to directly with traditional fluorescent lighting. Lux Magazine reports that two identical classrooms at Kazan State Power Engineering University were selected for the experiment; one utilised existing fluorescent lighting of neutral colour temperature without controls, the other had a new tuneable LED system installed including controller and panel with pre-set scenes. One hundred students, both male and female and aged between 17 and 23 took part in the test which measured responses at 2800K, 4000K and 5800K colour temperatures.
Although the experiment was over a relatively short period of time (one month), clear advantages of using colour tuneable lighting were noted; a 20% increase in the speed of task being carried out was observed as well a reduction in errors when lighting was tuned to 5800K when compared to the fluorescent installation.
On top of measurable evidence, students were also questioned about their overall mood and energy levels at the different colour temperatures, students reported feeling relaxed and drowsy at 2800K and alert and energetic at 5800K. Read more here
Human Centric Lighting & Motorsport
BMW motorsport racing at the recent Nurburgring 24hr endurance race were given adaptable pit garage luminaires and specially designed glasses incorporating coloured LEDs in the arms. It has long been known that cool, blue-hued light stimulates us and so drivers were given the blue LED glasses before each stint. In the time leading up to the change-overs, drivers who would be racing next would wear the glasses to make them more alert. Drivers who had finished their stint would then wear glasses with red LEDs to encourage them to rest and sleep, being given the blue again after waking and before the next stint. Lighting within the garage areas would also be turned to shift, aiding both concentration and rest.
Lighting & Sleep
Perhaps more important than turning our lighting on during the day is to ensure we have correct lighting at the start and end of the day, and eliminating light at night. Even the smallest amount of light spilling into our bedrooms at night can disrupt our sleep, so covering stand-by lights on televisions (which should be switched off anyway!) and covering gaps around doors are simple ways of reducing the amount of light we are exposed to while we sleep, complete darkness being required for melatonin to do its job. To engage the body’s circadian rhythms, the hotel industry may lead the way in introducing lighting that gradually comes on to wake guests up more naturally and evening time lighting colours and intensities for the end of the day. The hope is that this will filter down to domestic lighting.
The biological internal clock
The 2017 Nobel Prize for Medicine or Physiology was awarded to three scientists for their work in researching the internal clock. Jeffrey C Hall, Michael Rosbash and Michael W Young all published their initial findings in 1984 but have continued their research into the biological clock and how it is influenced by internal triggers and processes. Evidence for a biological internal clock was first documented over two hundred years ago in mimosa plants. Experiments showed that instead of reacting to light, there seemed to be a pre-programmed element to the opening and closing of the mimosa plants leaves. They would open their leaves in daytime and close them at night and repeat the process even when kept in total darkness. Work by the three award winners has continued throughout the past four decades into identifying proteins and genes which affect circadian rhythms and “how plants, animals and humans adapt their biological rhythm so that it is synchronised with the Earth’s revolutions.” – Nobel committee citation.
Human Centric Lighting & Wellness
Instead of putting the emphasis on illuminating task areas, there is now increasing focus on obtaining illuminance which improves the comfort and therefore productivity of the end-user. There has always been an ergonomic element to artificial lighting but with the advances in LED lighting technologies enhanced user comfort is being pushed to the fore of modern lighting systems.
It has long been recognised that lighting affects mood, and since the recognition of Seasonal Affective Disorder (SAD), it has become more well-known. During winter months and times of reduced natural daylight, sufferers can experience severe depression, the symptoms of which can be reduced with the help of naturally coloured artificial lighting.
Adaptive colour-changing lighting is not a new concept, but the LED revolution has meant that this is now a much more feasible approach to lighting. Studies have shown that there are benefits both to comfort and to productivity. The human body has natural rhythms which are directly influenced by levels and colour of natural daylight. These are known as circadian rhythms. High intensity, blue-hued light during mid-morning stimulates serotonin production making us more alert, while warmer tones of lower intensity light towards the end of the day signal the beginnings of melatonin production, readying us for rest and sleep.
A recent discovery of another type of structure within the human eye has furthered interest in circadian rhythms and how we can engage them. We have long known of rods (peak sensitivity 498nm, green-blue light) and cones (peak sensitivity 555nm, green-yellow light) but newly-found structures, the intrinsically photosensitive retinal ganglion cells (ipRGCs) have shown to be linked to mental alertness and are sensitive to wavelength approx. 470nm (blue part of the visible spectrum).
These relationships between light and human responses have now become part of a construction industry standard, the Well standard, which comprises seven areas for assessment: