John Downing, O.D., Ph.D., Director of the Light Therapy Department at the Preventive Medical Center of Marin in San Rafael, California, after twenty years of clinical research, has expanded the theory regarding the action of visually perceived light to encompass its effects on other areas of the brain, including the cerebral cortex, where it stimulates motivation, learning, thinking, creativity, memory, and even motor cortex body movements; the limbic system, where visually perceived light brings in the emotional impressions of the world; and the brain stem, where light helps to provide coordination and balance.

  When light enters the eye, millions of light- and color-sensitive cells called photoreceptors convert the light into electrical impulses. These impulses travel along the optic nerve to the brain where they trigger the hypothalamus gland to send chemical messengers called neurotransmitters to regulate the autonomic (automatic) functions of the body.

  The hypothalamus is part of the endocrine system whose secretions govern most bodily functions-blood pressure, body temperature, breathing, digestion, sexual function, moods, the immune system, the aging process, and the circadian rhythm. Full-spectrum light (containing all wavelengths) sparks the delicate impulses that regulate these functions and maintain health.

 

  

 

  Photobiologist John Nash Ott, D.Sc. (Hon.) satets poor light poses a serious threat to health. He believes that the kind of light adequate for maintaining health must contain the full wavelength spectrum found in natural sunlight.

  Dr. Ott discovered that most artificial lighting, both incandescent and fluorescent, lacks the complete balanced spectrum of sunlight and interferes with the body's optimal absorption of nutrients, a condition he calls "malillumination." Windows, windshields, eyeglasses, smog, and suntan lotions all filter out parts of the light spectrum and contribute to this problem. Research reveals that if certain wavelengths aren't present in light, the body can't fully absorb certain nutrients. Malillumination contributes to fatigue, tooth decay, depression, hostility, suppressed immune function, strokes, hair loss, skin damage, alcoholism, drug abuse, Alzheimer's disease, and cancer. It has also been linked, in a recent study at the Clinical Pathology Department of the National Institutes of Health, to a loss of muscle tone and strength.

  John Zimmerman, Ph.D, founder and President of Bio-Electro-Magnetics Institute in Reno, Nevada, says that most offices, even those with uncovered windows and the lights on, have a light level of only 500 lux (the international unit of illumination, one lumen per square meter), as compared to outdoor light, which has about 50,000 lux, or approximately 100 times more. Night shift workers are usually exposed to a light level of only 50 lux.

  Dr. Downing reports that by spending 90 percent of our lives indoors, under inadequate lighting conditions, we cause or worsen a wide range of health problems, including depression, heart disease, hyperactivity in children, osteoporosis in the elderly, and lowered resistance to infection. In order to keep up health it is important to be exposed to light containing the full wavelength spectrum found in natural sunlight.

  A recent study carried out by the U.S. Navy compared the risk of melanoma (a malignant, dark pigmented skin mole or tumor) for different naval occupations. It was discovered that personnel holding indoor occupations had the highest incidence rate of melanoma while workers in occupations that required spending time both indoors and outdoors had the lowest rate. In addition, a higher rate of melanoma occurred on the trunk of the body as opposed to the head and arms which are commonly exposed to sunlight. The authors of the study theorized that the anatomical site of melanoma suggests a "protective role for brief, regular exposure to sunlight."

  This is in keeping with recent laboratory studies that show vitamin D (whose production is stimulated by ultraviolet light) suppresses the growth of malignant melanoma cells. These new findings also call into question the belief that indoor occupations can provide safety for fair-skinned, freckled individuals who are at high risk for skin cancers. This and other studies indicate that an occupational deprivation of sunlight can lead to a vitamin D deficiency, which in turn could favor the development of melanoma.