At the core of our relationship with the sun lies an internal clock known as the circadian rhythm. This biological clock is governed by the suprachiasmatic nucleus (SCN) in the hypothalamus of the brain, which responds to light hitting the retina. For instance, when sunlight enters the eye, serotonin is released. High levels of serotonin are associated with boosted mood, calm, and focus.
Conversely, as the sun sets, the brain transitions to producing melatonin, the hormone responsible for sleep. Without enough exposure to natural light, the delicate balance of serotonin and melatonin can tilt, leading to Seasonal Affective Disorder (SAD).
Despite our biological reliance on the sun, modern life takes place mainly indoors. We spend a significant amount of our time under artificial lighting, which lacks the intensity and full-spectrum quality of natural sunlight.
Sunlight also plays an important role in our physical chemistry through the synthesis of Vitamin D. When sunlight strikes our skin, it triggers a process that converts cholesterol into Vitamin D. Low levels of vitamin D have been linked to negative side effects such as increased infection risk and cognitive decline.
To realign our internal clocks and protect our health we do not need to live outdoors, we simply need to expose ourselves to the sun more often. Architects and engineers are now attempting to implement daylighting into building design.
A light well is essentially a vertical shaft that pierces through the center of a building. These structures allow sunlight to reach the lower floors of buildings that would otherwise be entirely dependent on artificial light.
In modern designs, light wells are often capped with specialized glass that change transparency with the sun’s intensity. By lining the interior of the well with these materials, architects can “bounce” the sunlight all the way to the bottom of the well.
Another way sunlight is used in modern society is in Japan, where railway stations are high-risk areas for suicide attempts. To combat this, several major railway companies have installed blue LED lighting at the ends of station platforms.While the white sunlight of the afternoon triggers alertness via serotonin, researchers have also found that specific wavelengths of blue light can actually lower the heart rate, reducing impulsivity. In a high-stress environment such as a subway station, the blue light can serve as a calmer in an otherwise stressful situation.
The results of a study conducted over a one year period on the stations equipped with these blue lights found a remarkable 84% decline in suicide attempts. It is an amazing example of how the light in our environment can directly influence our thoughts and decisions.
On a larger scale, some cities are making use of Heliostats to bring light to areas that naturally get less of it. In towns such as Rjukan, Norway, the town stays in the shadows for 6 months a year because of its geographical location. To aid in bringing light to the small town nestled in a valley, engineers installed massive mirrors to redirect sunlight into the town.
These mirrors are computer-controlled to track the sun's movement as it passes through the sky, reflecting its light down into the town square. Furthermore, by concentrating the sun into the town square, a sort of communal place is created which may help bring people closer and foster a greater sense of community.
Moreover, for those who cannot always access the sun and do not have many other alternative methods, new “tunable” LEDs were created — coined “Circadian Lighting.” Traditionally, indoor bulbs emit a static white or yellow light. Since a static light does not allow our brains to easily differentiate between night and day, new LEDs that shift color throughout the day have been . These bulbs are designed to follow the sun’s natural progression throughout the day. This new technology is being rapidly adopted in places such as hospitals and nursing homes. In these settings, stable circadian rhythms are important for patent recovery and physical health.
The diverse ways in which we reclaim sunlight is important, whether it be through architectural design, sun-tracking mirrors, or LED lights. Regardless of the method, sunlight is critical to a productive life. For decades lighting has been designed for visibility alone, ignoring the physiological demands from our bodies. As we move further into the future, architecture and product designs will shift towards being palatable for humans, where our environments are engineered to support our biology.
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