Ancient medical books are filled with explanations of the importance of getting enough light. For example, the ancient Ayurvedic physician Charaka who lived in the sixth century B.C., recommended sunlight to treat a variety of diseases. For thousands of years people the world over have revered the sun as a great healer; some ancient cultures even worshiped the sun.
In 1980, new discoveries were ushered in the field of phototherapy. Scientists suggested that secretion of the hormone melatonin could be suppressed by exposing subjects to bright artificial light but not to light of ordinary indoor intensity. Melatonin is nicknamed "the chemical expression of darkness" as it is secreted at night and is believed to tell the body that it is time to sleep. Light rays impinging on the retina are converted into nerve impulses, which influence the secretion of melatonin by connections between the retina and the hypothalamus. This demonstration that one physiologic effect of light in humans, transmitted presumably via the hypothalamus, has a threshold intensity far higher than that required for vision, suggested that there might be other effects of light on the brain that require high-intensity light.
There is no doubt that the sun plays a very important role in our daily lives. In spite of all the warnings, we feel better after spending time in the sun. Today, most of the doctors and medical researchers view the sun more as a healer than a hazard. We know that lack of sunlight can result in nutritional deficiencies. Without sunlight vitamin D cannot be metabolized in the human body, which can result in rickets. Most enzymes, hormones and vitamins need light for proper functioning. Studies have shown that different lights affect different enzymatic reactions for healing purposes. For example, one of the first test a pediatrician do to a new-born baby is to check for jaundice. If found positive, they are placed under a blue light to cure the disease. So, most of us are given light therapy, without us being aware of it.
Monochromatic light promotes the DNA to use the lipoprotein in the area enabling the cell to function better as well as to produce collagen and elastin. Researchers furthermore wanted to find out "the effects of low-power light therapy on pain and disability in elderly patients with degenerative osteoarthritis of the knee." They have divided the patients into three groups. One group was treated with red light, one was treated with infrared light and the third group got no light therapy. Prior to the light therapy, the pain and disability was statistically similar among the three control groups. They found that pain reduction in the red and infrared groups after the treatment was more than 50%. Significant functional improvement was observed in the red and infrared-treated groups, but not in the placebo group. The experiment showed that low-power light therapy is effective in relieving pain and disability in degenerative osteoarthritis of the knee. Research conducted in Soviet Union and biological research done in the United States suggest that all living things may conduct light. Light has a great impact on synchronizing our circadian rhythms.
Light therapy consists of exposure to daylight or to specific wavelengths of light using lasers, light-emitting diodes, fluorescent lamps, dichroic lamps or very bright, full-spectrum light by a so-called light box. The light is administered for a prescribed amount of time and, in some cases, at a specific time of day. Light therapy directed at the skin is used to treat Acne vulgaris, neonatal jaundice or psoriasis. Light therapy which strikes the retina of the eyes is used to treat circadian rhythm disorders or insomnia and can also be used to treat seasonal affective disorder, with some support for its use also with non-seasonal psychiatric disorders (depression). It can help relieve winter blues and minimize jet lag or shorten abnormally long menstrual cycles; it can possibly even help relieve some symptoms of lupus, a serious disease involving the immune system.