The effect of ambient light on alertness, well-being and performance

In 2002, researchers at Brown University made a revolutionary discovery. They found a “third receptor” in the eye’s retina which is directly linked to the part of the brain which controls our circadian rhythm. For the first time, it became possible to research the link between access to light and how people react in a purely biologically sense.

Visually, biologically and emotionally

In earlier studies, research subjects had only been able to assess their reactions in terms of the visual task (visually) and how they felt (emotionally). But now the hormonal reaction can be measured as well. A study was carried out on the basis of VBE (Visual, Biological, Emotional) to provide more conclusive proof on the significance of ambient light for human well-being. 

How much light is best?

The aim was to investigate how people are affected by working in a room with three different levels of ambient light: 20, 100 and 350 cd/m2. Just like in the previous study, the room lacked incidental daylight and the light levels on the calculation plane, i.e. the work desk, were kept constant at 500 lux. The participants’ visual, biological and emotional reactions were studied during the test. The participants’ hormone levels (cortisol and melatonin) were also measured at regular intervals throughout the day. 

Ambient light is very important

The study showed that ambient light is very important for the visual task (visually), alertness (biological) and the experience of light in a room (emotionally). The most positive reactions were registered at an ambient light level of 100 cd/m2. The study also determined that the colour temperature of the light was not significant in terms of how the research subject felt or performed. 

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