I was reading the book Why We Sleep by Matt Walker earlier this year, and I found it fascinating to see how severe the impact of poor sleep can be on creativity, problem solving, decision making, productivity, learning and memory. These factors all have an impact on our work performance, and good workplace design should be focused on increasing all of these. In addition to these work related factors, sleep also has a significant impact on other health areas such as cardio-vascular health, brain health, immune system, and even longevity.

Parts of the book dealt with Circadian rhythm, and touched on the impact of lighting, especially LED lighting on our circadian rhythm, and it’s impact on sleep. As a lighting professional who’s core business is the design, manufacture and supply of workplace lighting, this has led me to me having an increased focus on human-centric lighting, and how lighting can be used to increase both health, and productivity in the workplace.

Circadian rhythms are physical, mental and behavioural changes that follow a daily cycle.

The best example is our need to sleep at night, when it is dark, and be awake during the day when it is light. This is an example of a light related circadian rhythm. Traditionally, our working hours, especially in white collar, office based roles are fixed, and set within daylight hours. But in general, these working hours are getting longer, with these additional hours coming from both an earlier start, as well as a later finish time. This means, especially at this time of the year with the days getting shorter, that we can be in the office before it is light, and leave after dark. We are also spending a far greater proportion of our time under artificial light.

This can be an issue at both ends of the day. In the morning, our circadian rhythm causes us to be wide awake and alert when the sun comes up, and is at its brightest. At the end of the days, as the sun goes down and it gets dark, our body starts to wind down, produce more melatonin and prepare itself for sleep.

Click here for more information on circadian rhythms

How is all of this a lighting issue? 

LED lighting emits a lot in the blue light spectrum. This blue light, or “daylight” can be very confusing for our bodies natural circadian rhythm. We have been very aware of this with our computers and smart phones for some time, and most manufacturers now have settings that enable a night mode which removes most of the blue light emitted by the screen. This is to minimize the disruption to peoples circadian rhythm who are working on a screen close to the time they need to sleep. The lighting industry is also very aware of this issue, but implementation on a broad scale in the Australian market seems to be quite slow. There are many reasons for this, such as cost, legacy equipment, the long time cycle between refurbishments, and possibly a reluctance to tackle this as a lighting issue. 

Good lighting design can be used to support our circadian rhythms. In the morning and during the day, higher lux levels and a higher (cooler) colour temperature will assist in alertness and “waking” people up. Toward the end of the day, the light level can be reduced, and a warmer colour temperature used to assist people to wind down as they approach their natural sleeping time. Apart from circadian rhythm, lighting should also be zoned in the office environment depending on task. Creativity, and the generation of ideas can be promoted by the use of warmer light, with lower light levels. Brighter, cooler white lighting is more energising, and promotes concentrated work. This should be taken into consideration when designing collab and break-out spaces, as well as the main office floor. Zumtobel has an excellent model where you can render an office space in different colour temperatures and scenes to see the different lighting effects. The images below are from this tool showing the same office in both warm white, and cool white.

Tune-able white lighting, and lighting control has been readily available for some time, and in my opinion, should be used far more than it currently is. Yes, it is more expensive, and yes, there is an increased overhead in the design, install, as well as the programming of the lighting control, but there are significant cost benefits to a well designed human-centric lighting system. This report from Lighting Europe on the Quantified Benefits of Human Centric Lighting goes into detail for many market segments such as Industrial, Office, Education, and Healthcare. The dollar figures are hard to extrapolate to the Australian marketplace, but the figures that I found particularly interesting were:-

In the Office Environment

  • 1.15% increase in productivity due to increased alertness and energising effect (approximately an additional 2 hours per month). There is also some research supporting productivity increases of up to 19%.
  • A reduction in sick days of 1% due to better wellbeing.
  • Increase of one year in the tenure of employees.

In Education

  • 15% improved cognitive performance of affected pupils.
  • 10% reduced healthcare and education costs due to less ADHD effects.
  • 18% improved treatment efficacy for mental disporders.
  • 2 year increase in the tenure of employees.

There are significant cost savings associated with these benefits. I think that the Australian market will slowly move to evaluating the cost benefits associated with the implementation of human-centric lighting and how it will off-set the increased cost. The change to LED lighting in the Australian market has traditionally been driven by reducing energy costs and programs such as VEET, iPart and Greenstar, and by Government regulation such as MEPS, and Part J6.2 of the BCA.



It is my hope that in the future, there will be a better understanding of the bottom line benefits of human-centric lighting, and more businesses and landlords will consider the technology when fitting out their office spaces.

Wishing you a good sleep!

Cameron Ely
Managing Director – Interglo Lighting

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