Dec 27, 2005 | by Wendy Weinert
Light, Sight and Feeling Bright
A sunny personality. A dark comedy. A bright smile. Simple phrases, yet they show the huge influence light has, defining the world around us even through the words we choose.
It seems simple, but most people never realize that how much light they get affects their mood, emotions and productivity. Understanding the ways in which light affects people has major implications for designers and the lighting choices they make.
Lighten the Mood
The end of the year brings shorter days to the northern hemisphere, which means less natural light from the sun. With less light, people experience changes to their moods, their emotions and even physical reactions like fatigue and lowered immunity to colds and diseases.
Depression, insomnia and fatigue may result from seasonal affective disorder (SAD) - also called the "winter blues" - and is commonly treated with light therapy to increase exposure to bright and full-spectrum light, thereby curing the symptoms.
While most people may not experience extreme depression with reduced lighting levels, they may still feel some effects. In earlier studies on light, results showed positive and negative moods were affected by the color of light, illuminance and color rendering index (CRI) levels. These results also varied depending on gender and age.
While natural sunlight is the best source of lighting, it is not always available in an interior space. Take into account how much natural light is in a room when selecting the color and intensity of lighting fixtures.
Adding bright lights or changing the color of bulb in a fixture could be an option to consider for a room's lighting scheme. Building in the flexibility to change light levels with a dimmer switch is also a good idea for a space where natural sunlight amounts vary with the season.
While most lighting research has focused on how much light is visually seen, recent studies suggest that light may also impact non-visual processes such as physical performance and mental tasks.
For residential lighting, this could mean adding bright lights in rooms requiring alertness and mental sharpness, such as a kitchen or home office. For non-residential lighting, the effects of light levels must be considered for irregular work hours (such as second- and third-shift workers) as well as the effects bright lights have on long- and short-term memory.
Here are just a few findings from the latest lighting research:
* Men performed poorest on long-term memory tasks in the artificial 'daylight' white lighting; women performed better than men in the artificial 'daylight' white lighting.
* Use 'warm' white lighting in areas where individuals will be performing short-term recall and problem solving tasks.
* Be aware that people whose sleep/wake cycle has been interrupted (such as people working a swing-shift schedule) report being more alert for a longer time when exposed to high (3,190 lux) or mid (230 lux) light levels than people exposed to low (23 lux) light levels.
* Consider the potential effects of light levels on alertness and performance for people that work at irregular times (night shift, etc.).
Humans live on a natural rhythm of light and dark. Our bodies are attuned to the light, responding to sunlight as well as bright indoor lighting. Whether you see yourself as a morning person or a night owl, you and everyone around you will have a natural reaction to how much light is in the environment