Most of us enjoy a good sunbath now and then, and even our doctors recommend a short dose daily. Did you know, however, that our bodies crave one kind of light in particular? Our bodies need light from the blue part of the color spectrum. This is one reason why sitting out in the sun makes you feel better than if you sit in sunlight coming through most window glass on the market today. Upon closer examination, sitting out in direct sunlight may be far better for you for other reasons as well.
Sitting in a light filled room gives us a false sense of security in some ways. For example, anti-reflective glass is often used in public places and businesses because it is able to transmit more daylight. The effect is bright light without reflection problems. Visibility is great and you can feel the heat of the sun through the glass. Harmful UV rays are penetrating the glass as well as light and heat. We can contract skin cancer and develop cataracts just as easily sitting in rooms like this but somehow we attribute special powers of protection to this glass where none exist. This is a very good reason to apply any number of various types of tinting to your home’s window glass.
Apparently this bright sunlight pouring into our homes is not having any positive effect on our biorhythms. The Circadian rhythm is the most well known of the various biorhythms and it is the one that is related to light sensitivity during any 24 hour period. Remember that light at the blue part of the spectrum? It is this light that our bodies apparently require for good mental and emotional health.
The retinas in our eyes have special receptors which are sensitive to blue light. These receptors convert blue light to light and dark signals and send them to the part of our brain which regulates our biological clock. This biological clock regulates melatonin levels which are important to mental health. Higher levels of melatonin are associated with depression. These melatonin levels play an important role in Seasonal Affective Disorder (SAD) or “winter depression” caused by a lack of exposure, over time, to sunlight.
Researchers at the Fraunhofer Institute for Silicate Research ISC in Wurzburg, Germany went to work on this problem and developed a glass that is especially transmissive to light from the blue part of the spectrum. They dubbed their invention “feel good glass.” They applied an inorganic coating 0.1 micrometer thick to regular window glass. They won’t reveal what the coating is comprised of but it works so well that it is being marketed through Uniglas GmbH & Company, KG of Germany. The “feel” of being inside a room with “feel good glass” is as if there is nothing between you and the sun.
While too much of one kind of filtered sunlight can be detrimental to us, a specific kind of light is necessary for well being. Our bodies can recognize good light from bad light. Our skin and eyes react negatively to UV rays but we seek out certain rays of sunlight to feel better. Blue light, it turns out, makes us feel good even when we feel “blue.” Tomorrow’s glass may well be able to accomplish all these goals in one product. Buying glass for a home or office may also include a doctor’s prescription.