The effect of lighting on our cognitive performance at work

24 Jan 11:00 by Karen Plum


Karen Plum, director of research and development, Advanced Workplace Associates


Light is a basic need for humans. It affects us physically, physiologically and psychologically. Recent studies have shown that insufficient or inappropriate light exposure can disrupt standard human rhythms, which may result in adverse consequences for cognitive performance, safety, and health.


How does light impact our brain?


We capture light information exclusively by the eyes using photoreceptors (rods and cones that detect visual information). In fact, our eyes are only sensors that detect colour and light variations and reflections. It is in fact our brains that translate this data into, what we would all understand as ‘images’. So our eyes don’t actually ‘see’, they only ‘sense’. It’s our brains that ‘see’.


Studies on animals and humans have shown that light stimulates a wide range of physiological responses like resetting the timing of the circadian pacemaker (your biological clock), and improving alertness.


Is all light good?


While light, and exposure to natural light is known to be essential to our physical and emotional wellbeing (according to medical experts and researchers), excessive brightness (i.e. glare) can be problematic. When there are uneven levels of brightness, this can cause tired eyes and be uncomfortable. The issue is that there is less contrast for the retina to detect, which causes strain. Glare can be present in many parts of the office, depending upon the direction of the sun and the amount of solar “management” within the building design.


Another contributor is the glare that can be generated by glossy workstations in the office. The trick here is to ensure the workstations are positioned such that the light doesn’t bounce up into the user’s eyes – we need sufficient light but minimum glare.


So what can you do?


Many offices these days concentrate on dedicating all the natural light to the open plan parts of their offices, so that the majority of occupants benefit from this condition (as opposed to lining the floors with offices or meeting rooms around the perimeter – thus depriving the rest of the office of the much-appreciated natural light). There is evidence that daylight keeps us more alert and accurate, whereas artificial light increases our levels of fatigue and sleepiness.


This is linked to the production of cortisol (stress hormone), which is produced in lower quantities the more time you spend in artificial light. Cortisol helps us handle stressful situations and impact mental clarity and performance. The other important mechanism is the production of melatonin (the substance that causes you to sleep or wake), which increases when there is little, or no natural light and falls when it is time to wake up. If you then work in artificial light all day, there are signals to increase melatonin production, leading to drowsiness.


That said, there is still tremendous variability in terms of how much light penetrates into the office space – and indeed depending upon the angle of the sun during the day, many people find they have to deploy blinds because the sunlight is just too strong.


People’s ability to move around to find the right lighting conditions will depend upon how mobile their role and technology allows them to be. Given that lighting is important, particularly for tasks requiring a lot of focus and concentration – try to be aware of the lighting and think about it when seeking out the conditions you need. Choose locations where you feel you have sufficient light for the task, without it being overly bright or dazzling from glare or too dim to focus on the task you’re working on.


Here are some thoughts:


  1. Find an area with high levels of light if you want to work on tasks that require high levels of concentration


  2. Work in different places with different lighting conditions (intensity and colour) to provide different moods and stimulation during the day


  3. Be aware of your surroundings – you may instinctively know that some places in the office are more comfortable for you than others…but you may not have realised why


  4. Try to choose places to work that are appropriate to the task that you are undertaking – we don’t always need very bright conditions and more subdued lighting can be conducive to more relaxed activities


    Give your brain a great day – be light aware!