When trace amounts of certain wavelengths of light are missing from your “light diet,” this can have a staggering effect on your health. -- John Ott
For eons, human beings have lived in harmony with the light of the sun. But only in the last hundred years or so, since its introduction, have we become rather well adapted to artificial lighting. The advent of artificial lighting liberated us from our dependence on daylight for the accomplishment of most activities, and in so doing it has fundamentally transformed human life.
Present-day researchers are concerned about certain unhealthy outcomes of our relationship with light, such as the lack of vitamin D and the increase in macular degeneration, migraine, depression, and even cancer in the general population.
Why then can light sometimes be healing and other times unhealthy?
When we consider the deleterious as well as the beneficial effects of different light sources, we must consider the ultimate reference, which is, of course, the light of the sun. The exquisite balance that our species has achieved with each one of the components of the sun’s light, including not only its spectrum, but also its rhythm, is part of our evolutionary story.
The Importance of Natural Light
One of the most efficient ways of cultivating a healthy relationship to light is to maximize lighting by the natural full spectrum of the sun at home, in schools, and in the workplace. Many architects are now more aware of this, and the tendency is to optimize the use of daylight in new buildings, not only from the point of view of energy efficiency, but also for the health of occupants.
Rosemann, Mossman, and Whitehead (2008) are exploring techniques that permit the efficient transmission of daylight up to fifty meters deep into the interior of large buildings, even in spaces without windows. In the near future we will see more of such new technologies as automated mirrors that follow the path of the sun, and optical guiding systems that regulate light delivery like the way ventilation conduits manage air flow.
Improving Your Relationship to Light
How can we improve the quality of our daily relationship to light? The following are some practical recommendations you can apply in the home. Note that some of these suggestions do not necessarily correspond to the official line of the medical establishment or the lighting industry, but they do reflect a wider perspective about light stemming from the accumulated knowledge that has been compiled over the years by my colleagues of the ILA.
Prefer halogen or incandescent bulbs, because of their significant infrared content as well as because their light spectrum is closest to that of sunlight’s broad continuous spectrum. A side benefit to using incandescent and halogen bulbs during a good part of the year in Nordic countries is that the energy “wasted” through heat is not lost because it contributes to the heating of the house.
Avoid, as much as possible, fluorescent and compact fluorescent bulbs because of the strong, discontinuous lines in their light spectrum as well as the toxicity factor from the presence of mercury.
If you use LEDs, choose the “warm white” type (2,500 to 3,000 K) to minimize the effect of blue within their spectrum, which can interfere with the circadian rhythm, especially in the evening.
Avoid fluorescent and LED bulbs with excessive flickering, to minimize exposure to unnecessary environmental stress caused by “noisy” light. Since flicker levels are not readily visible to the naked eye a light noise detector (such as a light-to-sound converter) may be useful to select better light bulbs. Avoid the use of dimmers with LED bulbs, as dimming commonly leads to increased flickering.
Avoid all light sources in your bedroom at night, including alarm clocks, night lights, and the like. Use curtains or shades to shield all excess light from the outside, which is to say anything that is brighter than the light of a full moon. If you need to use an illuminated alarm clock, choose a red or orange color to minimize any interference with the circadian rhythm.
Spend as much time as possible outdoors in daylight to maintain a properly synchronized circadian rhythm.
Try to expose your body (without using sunscreen) at least occasionally to the full light of the sun. While carefully respecting the sensitivity of your skin, allow it to benefit from the effects of heliotherapy and natural ultraviolet light. Expose the largest possible surface of your body, at the same time giving proper protection to the eyes and head. A few minutes will suffice. Aim for those periods when the sun is high in the sky to optimize the biosynthesis of vitamin D. At other times of day you risk being sunburned without receiving the benefit of increased vitamin D.
Expose yourself at least occasionally to daylight without your glasses or contact lenses (including sunglasses) on. While carefully respecting the sensitivity of your eyes, allow them to receive the natural total light spectrum. Of course, never look directly at the sun, which could damage your retina.
Sunlight Combats Myopia
As we explore the incomparable qualities of natural light I am reminded of a recent article by British engineer Richard Hobday, an authority on sunlight and health in the built environment. Hobday (2015) has established a connection between the rapid increase of nearsightedness in schoolchildren over past decades and the quality of light they are exposed to on a daily basis. This question is significant because in China, for instance, it is estimated that now as many as 80 percent of students are nearsighted by the end of high school. Hobday (2015) quotes a 2013 Taiwan study that found a 50 percent reduction in myopia in children who go outdoors during class recesses.
This worldwide development seems to have begun in the 1960s, at a time when the accepted norm for the interior of schools went through a transition, moving from the natural light of day, with large windows, to artificial, usually fluorescent lighting. Obviously, there were probably many other factors involved, but recent studies have confirmed that myopia can be countered by increasing the number of hours that children spend outdoors, no matter what physical activity they are involved in.
Many researchers conclude that being exposed on a regular basis to very bright daylight (generally of the order of 100,000 lux, as opposed to 1,000 lux under artificial lighting) is essential to the visual health of children.
©2018 by Anadi Martel.
Reprinted with permission of the publisher,
Healing Arts Press. www.InnerTraditions.com
Light Therapies: A Complete Guide to the Healing Power of Light
by Anadi Martel
(Originally published in French: Le pouvoir de la lumière: À l'aube d'une nouvelle médecine)
A comprehensive guide to the therapeutic benefits of light and color and how they affect our physical and psychological well-being. * Shares scientific research on how different wavelengths of light influence our cells, brain function, sleep patterns, and emotional stability * Examines several forms of light therapy, including chromotherapy, heliotherapy, actinotherapy, and thermotherapy * Explains how to use light and color therapy, maximize the benefits of sunlight, and avoid the health risks of new light sources such as compact fluorescents and LEDs.
About the Author
Anadi Martel is a physicist and electronics designer, who has acted as a consultant for IMAX, Cirque du Soleil, and the Metropolitan Opera of New York. For more than 30 years he has researched the therapeutic properties of light and the interaction between technology and consciousness, leading to the creation of the Sensora multisensorial system. His sound spatialization devices have been used around the world, including by NASA. He serves as President of the International Light Association (ILA) and lives in Quebec.