From Thomas Edison's empty glass bulb to AI-controlled LEDs, hundreds of years of constant evolution have passed, which culminated in what we now know as artificial lighting. Edison could not have imagined how dependent we would become on his invention almost two centuries later. It led to a way of life where we spend up to 90% of our time in enclosed spaces deprived of natural light, such as shopping centers and offices. Places where artificial light remains constant throughout the day, without any variation of color temperature or luminous intensity are where artificial lighting practically eliminates day and night differences.
However, with the evolution of studies on our well-being, especially regarding the direct relationship between natural light and metabolism, it has been proven that artificial light should go much further than just helping us see. It can also help maintain our body working correctly both biologically and psychologically. Research indicates that the "biological clock" influences daily activities. Light variations - from sunrise to sunset - send precise signals to the brain that interprets them and transmits them to the human body, triggering specific responses. Blood pressure, body temperature, and hormone production vary over 24 hours and according to the visual information we receive from light. In this context, a light source that does not change throughout the day does not fit with the human body since different light stimuli are necessary to perform daily functions more accurately.
Human Centric Lighting (HCL) emerged as a way to respond to this impasse, offering lighting conditions in harmony with the biological clock. A technology made possible thanks to innovations such as LED lights and digital control systems. Meeting the current lighting requirements with human-centered projects, HCL represents a cultural change, seeking to create a healthier relationship with the artificial environment in which we live. Human-centered lighting ensures that the temperature and intensity of light are individually tailored throughout the day, even matching, albeit artificially, natural lighting that precedes it. It is undeniable that natural light is always the best option. However, this concept seeks to approach its qualities as closely as possible in an efficient combination with other artificial sources.
Its aspects may vary in spectrum, intensity, and duration. Morning natural light informs our biological clock that the day has begun, activating bodily functions. At this moment, cool white light with wavelengths in the blue spectrum can stimulate the body in the morning or when we need to concentrate and be alert. On the other hand, at sunset, the lighting decreases, which increases body deceleration. At this moment, warm white light can help us relax and unwind.
The advantages of this system are numerous. It can be applied: as therapeutic lighting, playing a role in the treatment of patients suffering from psychiatric or dementia-related diseases; as ergonomics lighting, to produce light of different colors to create ideal visual conditions for work; or as biological lighting, imitating the qualities of sunlight to improve human performance, well-being, and support a better circadian rhythm. Regardless of its application, HCL lighting makes environments more welcoming. It influences its users' behavior and the performance of functions that require attention, focus, and quick response time.
In more specific programs, such as schools, human-centric lighting can be used not only to stimulate students' and staff's circadian rhythms but also to improve alertness during tests and tasks that require focus, since lighting is linked to productivity in the classroom. In the offices, lighting can affect employee alertness, mood, cognition, sleep patterns, and health. Inappropriate lighting can cause visual fatigue, headaches, or even difficulty discerning a risk element due to insufficient lighting. Finally, it offers hospitals several benefits. They include aiding the quality and standard of sleep for patients who spend their time indoors.
As can be seen, its applications and benefits are numerous. Together with cutting-edge software and sensors, human-centric lighting respects biological needs meeting demands perceived as natural to offer environmental comfort and well-being that return us to a connection with nature, even though it may seem contradictory.
This article is part of the ArchDaily Topics: Light in Architecture, proudly presented by Vitrocsa the original minimalist windows since 1992.
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