Our aim is to find factors that most impact our cognitive performance, so individual organisations can adopt the best practices to get everyone’s brain in peak condition. Now, we consider the effects of lighting in the office.
Light is a basic necessity for humans. It affects us physically, physiologically and psychologically. Studies have shown that insufficient light exposure can disrupt human rhythms that can result in adverse consequences for cognitive performance.
Our eyes are the only sensors in the body that can detect colour and light variations and reflections. Our brains then correlate this data into what we see as ‘images’. So our eyes don’t actually see images, they see light and colour variations, which our brains transform into pictures.
Studies have proven that humans depend on light to reset the timing of their circadian pacemaker (your biological clock), as well as improving alertness and other physiological responses. Our biological clock rhythms are kept in sync by a variety of cues, a main one being light. High frequency and intense lighting promotes alertness, without this stimulus, the body can think it’s time to conserve energy and continue to rest.
In 1993, a well-known study was carried out in an office environment, measuring the brainwave patterns (EEGs) of research subjects, whose delta waves (and indicator of sleepiness) were reduced when lighting levels were lower. The conclusion was that bright light has an alerting influence on the central nervous system (Kuller & Wetterberg, 1993). For comparison, a clear day will array about 10,000 lux of lighting, ambient lighting levels of around 300 lux are felt suitable for most office tasks (with higher levels provided through task lighting where additional detail is needed).
It has also been shown that blue light is helpful for increasing alertness and accuracy, when compared to ‘normal’ light. Advanced lighting (LED) technologies have also been shown to promote increased alertness and visual cognitive efficiency among workers when compared to more traditional alternatives (Hawes, 2012).
Brightness levels contribute to our perception of spaciousness and the degree to which they look appealing.
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 like glare, can be problematic. Uneven levels of brightness can cause tired eyes and discomfort. 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.
Most offices dedicate all natural light to open plan parts of the office, so majority of employees can benefit from this condition, as opposed to lining the floors with meetings rooms and closed workstations. There is evidence that daylight keeps us more alert and accurate, whereas artificial light increases our levels of fatigue and sleepiness. So the more windows exposing natural sunlight into the office, the better at keeping employees alert and accurate.
Lower quantities of cortisol (stress hormone) are produced when a person spends more time under artificial lighting. 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 take up. If you then work in artificial light all day, there are signals to increase melatonin production, leading to drowsiness.
People’s ability to move around and find the right lighting conditions will depend upon how mobile their role and technology allow 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, matching the right noise and temperature to suit your needs.
If you are carrying out a task which requires high levels of concentration, then it is best to find a well-lit area, preferably with natural sunlight. Remember that different lighting conditions (intensity and colour) provide different moods and stimulations during the day. More subdued lighting can promote more relaxed activities, therefore can be better to work in depending on the task at hand.
Finally, it’s best to always remember, light levels are key to our sleep patterns and circadian rhythms.