Can good lighting compensate for low daylight levels?

Together with researchers at Lund University, Fagerhult has clarified the relationship between light, alertness, wellbeing and performance.

In 2002 new findings were presented that changed the parameters of research into lighting. A U.S. research team had identified a third receptor on the retina. This receptor was the link between the eye’s intake of light and our hormonal system, a connection which had remained elusive for numerous years. The research scientifically confirmed what we all already knew: that daylight makes us more alert and feel better. This then posed the question, are these findings also applicable to artificial light? And, if so, what type of light is of greatest importance for our wellbeing?

Measuring of hormone levels

Fagerhult has conducted a variety of research projects, encompassing both laboratory and field studies. Since 2005, we have been working in conjunction with Lund University and Torbjorn Laike, who is internationally renowned for his research into the non-visual effects of light. Due to their levels of high public interest, funding has been provided by The Swedish Energy Agency to support these projects.

Visual, biological and emotional

In the different studies, we examined how subjects react to different light levels and light spectrums, visually, biologically and emotionally. Recording how they managed the visual task, how they react hormonally and how they experience light emotionally. Their cortisol levels were measured, as this is connected to the production of the alertness hormone, to see how this was affected by the light levels.

The important ambient lighting

The results show that what we call ambient light, i.e. light onto the walls and ceiling, is of great importance. This is because the human eye is accustomed to receiving the largest share of light vertically from the sky. Direct light into the eye might result in glare, causing the pupil to constrict and limit the intake of light.

Feel best with ambient light on about 100 cd/m2

Studies show that people feel better, are more alert and work best at an ambient light level of about 100 cd/m2.­ Through a 2009 field study, undertaken in a middle school in London, we could pinpoint that an ambient light of around 100 cd/m2 could improve student performance, alertness and well-being.

We are all positively influenced by light, even if it is artificial. But the obvious fact is that a combination of a daylight and good artificial light is the very best – not least from an energy point of view!

Read more about research where Fagerhult partisipated

Preferred luminance distribution in working areas – T. Govén et al 2002
The background luminance & colour temperatures influence on alertness & mental health – T. Govén et al 2007
The influence of ambient light on the performance, mood, endocrine system and other factors of school children – T. Govén et al 2011
The impact of lighting controls on energy consumption of lighting in classrooms – T. Govén et al 2011
The experience of ambient light from common light sources with different spectral power distribution – Light emitting diodes (LED) vs. 3-phosphorus fluorescent tubes (T5) – T. Govén et al 2012

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