Quick Guide to How Light Affects Our Body.

Circadian Cycle & Light

Designers of interiors now have the ability to make informed choices about how the light used within a building will affect the occupants that inhabit it. Whether a professional designers of homeowner, make the best choices of lighting for your space and harness the power of light.

It has been a while since we discovered our third eye. In fact, it was 2002 when a German University scientist discovered a new set of sensors in the retina that triggers mood responses in our mind and body when exposed to light. The findings initiated a revival in the interest of circadian rhythms in the lighting world and with it a prediction that smart lighting would dictate lamp design into the next decade. However, many years later, one is left wondering ‘what happened’ with little evidence that the science has been fully embraced by the lighting & interior design sectors.

Check put this brilliant short Circadian Cycle video & how our bodies respond to light

Light Directly Affects Our Body Clock

It would seem that light means more to us than just brightness – it has a far more profound effect than merely aiding vision. The SCN cell is hardwired directly into our internal body clock within the brain which research has discovered is incredibly accurate and sends vital signals throughout our anatomy.

Each individual’s clock will run a 24 hr cycle but it is often not exact – it can vary in terms of accuracy. Our bodies recalibrate this clock with light every day. It is why blind people have the added challenge of becoming out of sync with day and night. Until 150 yrs ago we were all happily dependent on natural daylight, firelight, and candles. Since then we have been changing our natural pattern with artificial illumination. But we ignore the importance of this light cycle at our peril.

The Colour of Light Stimulates the Body

This SCN cell is most stimulated by the wavelength of light within the blue spectrum. Give it a blue-enriched diet then it’s firing on all cylinders. Give it red and we’re getting ready to sleep. Naturally – if we are over-stimulated at night we cannot rest and understimulated in the morning we can be ineffective. Take the whole body clock into account and a lack of balance can lead to stress, depression and other illnesses.

Colour Temperatures of Light Changing in a Day

The Brightness of Light Affects Our Bodies

The brightness of the artificial light we are choosing will also affect the bodies circadian cycle with the brighter the light the more stimulated and alert the occupant will become. Brightness is measured in lumens, with the higher the lumen level of a lamp the greater the output and brightness.

Any lamp or light fixture with an 800 lumen output or more is considered a higher level of output from a single source, which is grouped in multiples will create a bright enough environment to affect the users.

The Duration of Light Exposure Affects the Body

The length of time someone is exposed to brighter light and/or a particular colour of light, the greater the opportunity there is for the brain to be stimulated and suppress the sleep hormone melatonin. A quick look

Use the Power of Light in Interiors

These 3 factors of Colour, Brightness and Duration should be considered to help create a lighting design that can harness the power of light for the benefit of the user. For example, ensure there is a blue enriched white light during the day and replace that with a warmer richer blue free colour of light for the evening to allow the body to prepare for rest and sleep.

Despite all the science, the truth is that the methodology of blue and red light has not taken hold of ‘lighting industry’ imaginations – judging by a recent statement by the International Commission for Illumination things are still slow to ignite.

“…despite great promise, there are as of yet no protocols for providing specific “circadian” benefits in buildings for general populations.”

Blue enriched white light prepares astronauts to be more alert prior to space walks

Circadian Lighting Control Used in Space

As an example of a good balance of light, NASA operated strict circadian lighting control within the International Space Centre; prior to a spacewalk, the astronauts will subject themselves to a period of 6500K blue-enriched light, invigorating the body. To induce sleep they will bathe in very warm (blue free) light.

Circadian Lighting in an Office Environment

The morality of deliberately using light to stimulate the workforce to create a higher productivity is called into question, however the science is proven that the suppression of melatonin will yield a greater alertness which in turn should at least help towards longer periods of concentration from the occupants. The office environment can fight against the afternoon graveyard shift of post lunch workers with a blast of bluer white light and again 30 minutes before the end of the working day to increase alertness for the journey home.

Office environment utilising lighting’s power to create an alert workforce

Suggestions on How to Create Circadian Lighting Schemes

In a practical sense, there is an absence of affordable or accessible systems on the market – apart from some mid-market Building Management Systems. Yet I believe we can work with circadian know-how in all our projects at a relatively low cost.

Circadian Lighting Using Standard Light Fixtures

Using a range of differing colour temperature LED lighting units including; strips, downlights, and spots. Operating on several separate lighting circuits, with a compatible dimmer, an interior lighting scheme can be easily tuned to suit the time of day.

Why not talk to us about your affordable lighting options for your next project. Remember, clever lighting schemes don’t always need to be smart!

Andrew Orange, the owner of Orange Lighting qualified and worked as an interior designer in 1993 before specialising in lighting working on high profile projects based in London. Since starting Orange Lighting Ltd in 2003 he has been sharing his knowledge and unique teaching style mostly to his designer clients, offering practical real life advice born from running a busy consultancy and lighting supply business. Launching in 2020, his blog has evolved into Quick & Easy Lighting, curating some 25 years design experience into making the lighting choice and design process achievable and easy to understand for all.