Key words: SAD Phototherapy Full Spectrum LED Lighting
In the Swedish capital of Stockholm in winter, whenever the sun sets at 15:00 pm, the whole city sinks into the dark and gloomy.
More than half of people in this environment will become depressed and lethargic, and looks like a vibrant different person from
summer. 3% of people even need to go to doctors. Before the 1980s, people know nothing about the causes of the personality
change occurs with seasonal variations. Later, Dr. Norman E. Rosenthal, who worked at the U.S. National Institutes of Health
Psychology as senior researcher, and clinical professor of psychiatry at Georgetown University, linked the short and dark
winter's day and the onset of seasonal depression. He and his colleagues began to study this phenomenon and defined it as
Seasonal Affective Disorder (SAD).
No one knows the causes of SAD. Experts believe that the light is playing a certain role to SAD patients. With more light, you can
sometimes improve their mood. Melatonin is also considered being associated with SAD. Melatonin is secreted at night, There
would be more melatonin in human blood in winter than in summer, making human body temperature drops and becomes lethargic.
Scientists have confirmed that SAD patients’ symptoms usually are improved after light therapy, which may owing to the light
blocked the generation of melatonin. Most SAD patients need to spend 2-3 days in the
bright sunlight to eliminate abnormal symptoms. Also, you may find that when people travel closer to the equator, the symptoms
Back in ancient Greece, Hippocrates period, when doctors had learned many aspects of the human body - both physical and
psychological aspects, are resonating with colors in spectrum. They found that the color will affect human emotions, and even
lead to many psychological disorders. In the book < COLOR ALCHEMY >, America's chief color designer Jami Lin gave a detailed
description of the psychological impact of color to human’s thoughts and feelings. And as preface for this book, Burton Jacknow
who has a PHD in The physical organic chemistry at Columbia University, had mentioned the incredible effects of light on human
body and spirit, namely - Cure Effect. In a major test conducted by National Aeronautics and Space Administration (NASA), the
researchers used colored LED light penetrate human tissue deeply to promote wound healing, accelerating the growth of human
tissue structure, and eventually proved the color wavelengths can affect the chemical structure of the human body, stimulating
natural growth in the healing process.
The best way to avoid SAD, is more exposure to full spectrum natural sunlight. If your mood is changing along with the sun in
winter, you can seriously consider taking a vacation to a sunny place, it can dramatically better you healthy and mood throughout
the winter. Dr. Norman E.Rosenthal said, when people receiving the ambient light of full spectrum, his body releases significantly
reduced melatonin, by which the depression is eased, and the mood has been improved significantly. Compared to those receiving
light with certain wavelength, are subject to SAD.
For those who live in the north as well as those who stay indoor all day, the sunshine is almost a luxury during the most of the
time in year. However, general indoor lighting products have a serious lack of spectrum. For example, a primary school in
Vermont's tried to installed ultraviolet (UVB) fluorescent lamp in three classrooms. Before using this yet, the absenteeism caused
by illness of children in experimental group and the comparison group are the same, but after replacing the fluorescent, the
sickness rate of those kids who enjoyed the light with ultraviolet was reduced by 40% than the comparing group. Children have
been relatively easy to get sick particularly in winter and spring. However, this situation could be changed by using lighting
products with part of ultraviolet. That is to say, our immune system could be significantly affected by the length and quality of
our daily light we exposure in.
If you can not go to a warm sunny place, you can also think of ways to make yourself at home, receiving the maximum amount
of sunlight. Or change the lamps in your home and office into a full-spectrum lighting products.
If the situation is really bad, you might consider phototherapy, although this has to be studied on the optimal irradiation therapy
sessions,irradiation time and irradiation intensity. But for SAD people, two hours a day, from six to eight in the morning would
be effective. Of course, some take longer sunshine hours, or increase the time of being illuminated at night. Light intensity should
be 2500 lux, which is approximately equal to the received luminosity of standing at the window in spring.
Daylight glasses for SAD patient, developed by Denmark engineer
Of course, just like the author of < Healthy Pleasures > Robert Ornstein, Ph.D. & David S.Sobel, M.D. said, most time it is not
the light affecting your mood, but your attitude towards yourself and look at the world.