FX light focus: body clocks


Harnessing the knowledge we have about circadian rhythms and adjusting light levels accordingly throughout the day (and night) can pay out huge benefits.


FX

Words by Helen Loomes

For millions of years natural light has governed the pattern of people's lives. We have become accustomed to sunlight and the natural day/night rhythm throughout Evolution. Daylight changes in intensity, colour temperature and direction, all according to the season and time of day.

We now know that our biological circadian rhythm responds to this natural cycle. We all like to feel we are individuals, but in reality we are very predictable. The secretion of our hormones, which determine whether we feel alert or sleepy, able to concentrate, and even our body temperature, are directly influenced by certain wavelengths of light entering through our visual system. However, these stimuli avoid the optic nerve and have a direct pathway through to the pineal gland, keeping our internal time clock in tune with the natural passage of time.

With the advent of artificial lighting we have changed the conditions that our body relies on to have a normal sleep/ wake cycle. It certainly seems a good idea to give ourselves the best environment possible to help us to perform at the height of our ability, and research is proving that this is the case. Many studies are showing us that we can improve concentration and the ability to learn by incorporating the correct lighting conditions.

Lights Focus

Ideally, we need a low intensity of light with a warm colour temperature to start the day gently, with an increase in intensity and change to a cooler colour temperature, where the blue wavelength is especially important, to energise us.

That process then needs to be reversed in the evening, and we need to make sure we have a truly dark environment during the night for sound sleep. The two areas where this is most relevant is within education and healthcare, especially the care of the elderly, and these are also the areas where we can see the most dramatic results. There is a word of caution here, however - we should not try to manipulate people to perform better, but rather to replicate what would happen naturally under daylight.

It is difficult to stipulate exactly what we should be doing, but interest has stepped up a gear and now many bodies are investing in this type of research. For instance, the German government is investing €5.7m, along with the Fraunhofer Institute (Europe's largest application-orientated research organisation) to try to get more specific answers.

On a smaller scale our hospitals are investing in enhancing the healing environment through the King's Fund, an English health charity. This is a practical investment in a small number of hospitals to improve many aspects of the healing environment, including lighting, wayfinding, good contrast and supporting the day/night cycle, and the results are proving very beneficial. For the elderly this can be measured through decreased falls and accidents and, anecdotally, with better quality of sleep.

At Ipswich Hospital NHS Trust, for example, three wards for those with dementia have been improved by using daylight wherever possible, adding sufficient domestic-style elements and exposing people to the 24-hour cycle of light and dark. This means luminaires are programmed to provide warmer, lower-intensity light in the morning and evening, but also much higher levels of cooler white light during the day - higher than we normally would use in this environment - with 600 lux in many rooms. Some studies go as far as recommending 1000 lux. Key elements such as doorways and recognisable features are also highlighted to aid wayfinding and create a safer, more confident environment.

At the Maria-Hilf Hospital in Brilon, Germany, humancentric lighting has been installed in the department of geriatrics in all patient rooms and corridors. Here all the LED lighting is controlled through a central management system to give 600 lux at eye level and 300 lux at floor level in corridors, and between 600 lux to 1,500 lux during the day in patient rooms, again with a varying colour temperature of between 3000K and 6000K.

The Bridge Academy in Hackney, where controllable lighting was designed by BDP Lighting
The Bridge Academy in Hackney, where controllable lighting was designed by BDP Lighting

There are also impressive results in the educational sector. In a study where the classroom teacher was given the ability to adjust the lighting according to the activity and time of day, attainment levels in reading increased dramatically compared to a control classroom. Errors relating to concentration were also down, and reduction in restlessness was the most impressive difference. The lighting for this new group of classrooms involved suspended direct/indirect fittings with dimming controls and the ability to mix colour temperatures between different banks of LEDs. To make it simple for the teacher there were four preset lighting conditions. This type of technology is readily available with the development of LEDs and does not cost much more than the conventional luminaires used in the control group.

Another case study where there have been dramatic results is the Bridge Academy in Hackney, which went from being a failing school to being in the top 25 per cent of schools adding value. While this was not solely down to the lighting, it was one of the elements that transformed the academy. Here BDP Lighting worked to bring as much natural daylight as possible into the space supplemented by a variety of artificial lighting. This was zoned to give different lighting conditions for different activities. Areas furthest away from natural daylight were used for more relaxed activities and given a warm colour temperature, while the areas that naturally had daylight were supplemented by cooler lighting conditions and used for more intensive study.

While understanding our biologically specific requirements is crucial, I think there's another aspect which is very important. We can have a very powerful emotional response to our environment - just think of a beautiful sunset and how it can make you feel, or a bright summer's day that lifts the spirits. Is what makes us think that something is beautiful biologically programmed into us? Or is it learned behaviour? A child's face is designed to be appealing because they need us to look after them. Perhaps we react to a sunset because there is something within that sunset that we need biologically to function better? If we need changing lighting conditions throughout the day to satisfy some biological requirement, do we also find that people actually like it that way? Is it a built-in natural emotional response?

In my experience this is certainly the case and I think this will become the biggest lighting debate over the next five years. As our population increases and our living spaces become smaller, the quality of those spaces will become much more important. We will need our personal space to work harder for us and interact with all of our needs, biological and emotional.








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