Physiological Impacts of Lighting and Design Considerations

Posted by Alex Wu on


Lighting is a medium that plays a major role in making visual perception possible.
We experience the environment and surroundings first by light entering our eyes.
Besides visual perception, lighting can also cause some physiological effects.


Many studies show that the correct lighting in a particular environment at a specific time can have major benefits, such as stronger synchronization at the office, improved learning at school, improved sleep and recovery in hotel rooms, improved daytime activity and sleep at night in nursing homes, and improved physiological parameters of passengers on airplanes. Some physiological effects of lighting include affecting our mood, well-being, comfort, and relaxation. Lighting can also affect our circadian rhythm, which dictates our sleep pattern, our concentration, alertness and hormones. Some positive established effects of good lighting design are: shortened sleep onset, increase in deep sleep, improvements in mood, stabilization of rhythm, decreased depression, activation of cognition and shortening of reaction time.


Since lighting has these extremely important physiological effects on people, it is important to get it right. It can mean the difference between a comfortable and healthy environment to an unproductive or stressful one. In architecture, lighting is often treated as a secondary concern in comparison to form creation, yet it is crucial to the user experience of a habitat.


Here are some things lighting designers need to consider, in order to create a comfortable environment:



Glare

It is paramount for the amount of glare in a certain space to be as low as possible. This parameter is especially important in areas where people will spend a large amount of time in e.g offices, schools, rest homes and other healthcare areas. Glare can cause discomfort, eye fatigue and in more serious cases, a decline in eye health.



Normal downlight vs Low glare linear downlight vs. Low glare mini downlight


The amount of glare a room will have depends on many factors, such as reflection from items in the room e.g computer screens etc. However, in terms of the light fitting itself, there are also ones designed to have a low glare rating. This can be due to the design of the reflector as well as due to shielded fittings. A light fitting with a unified glare rating (UGR) of less than 19 (UGR<19) is usually considered 'low glare'. Selecting a low glare light fitting to begin with one way to decrease the glare in a space.

 


Positioning

Where a light fitting is placed is also very important in order to create a comfortable environment. For example, the lighting in a badminton court is usually placed on either side of the court instead of directly above it. This placement technique reduces glare during a match and therefore creates a more comfortable environment. It is best practice to position lighting with its beam concealed from our line of sight.



Colour Temperature

The colour temperature of the light is also very important in determining the mood of a space and it also affects our circadian rhythm. Colour temperature is often divided into 3 main groups: warm (~2700K-3000K), natural (~4000K) and cool (~6000K-6500K). A warm light is good for promoting sleep and relaxation, whereas a cool light is used to create alertness, boost concentration and creates a working climate. A natural light is often used in neutral areas where it is very close to a natural sun/daylight colour.



Brightness and Uniformity

Ensuring that the correct lux level for a specific room/area is achieved is a necessity. The greater the luminance, the easier an object is to see. The minimum lux level requirements for different rooms/areas varies, e.g a regular stock warehouse could have a lux level of 200lx whereas a mechanical workshop may have a lux requirement of around 750lx. Depending on the type of room and activity occuring in that room, the lux level required would differ. When we are in a room like an office, our gaze constantly switches from a bright screen to a darker wall. This difference in brightness means our eyes are constantly needing to readapt, and therefore tired quickly and our well-being declines. Good uniformity of lighting in a room is beneficial to eye-health, but may make a monotonous impression. Finding a good balance in less crucial areas such as a restaurant is necessary in order to create nice contrasts and dynamics with light and shadowing, which help to improve the mood.




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