Condition: Academic Performance (students)

Summary: Several studies have shown that full spectrum light (natural sunlight) has unequivocal positive effects on students. Specifically, students with natural sunlight (1) learned faster, (2) had overall higher test scores, (3) grew faster (physically), and (4) had 1/3 fewer absences due to illness. These benefits of natural sunlight were in addition to other well-known  effects such as improved mood and improved sleeping patterns. The same studies noted that students exposed to natural sunlight had 2/3 fewer cavities than expected.

Source: Grangaard, E. (1993). “Effects of Color and Light on Selected Elementary Students.” Unpublished doctoral dissertation, University of Nevada-Las Vegas, Las Vegas, Nevada; Helveston, E.M., Weber, J.C., Miller, C.O., Robertson, K., Hohberger, G., Estes, R., Ellis, F.D., Pick, N., & Helveston, B.H. (1985, March). “Visual Function and Academic Performance,” American Journal of Opthamology, 99 (3), 246-355; Sydoriak, D.E. (1984). “An Experiment to Determine the Effects of Light and Color in the Learning Environment.” Unpublished doctoral dissertation, University of Arkansas, Little Rock, Arkansas; Hughes, P.E. (1982,March-April). “School Lighting for the Total Person: APsychobiological Approach.” CEFP Journal, 19 (2), 4-7; Wohlfarth, H.(1986). “Color and Light Effects on Students´ Achievement, Behavior, and Physiology,” Edmonton, Alberta: Planning Services Branch, Alberta Education; Zamkova, M.A. & Krivitskaya, E.I.(1966, April). “Effect of Irradiation by Ultraviolet Erythema Lamps on the Working Ability of School Children,” Gigiena in Sanitaria, 31, 41-44 (translated by Duro-Test Electric from Russian original); W.E. Hathaway, J.A. Hargreaves, G.W. Thompson and D. Novisky. “A Study Into the Effects of Light on Children of Elementary School Age - A Case of Daylight Robbery,” (Edmonton, Alberta, Canada: Alberta Education, 1992).

Condition: Aging (see also “Longevity”)

Summary: As humans get older, melatonin levels decrease, but the question arises as to whether this decrease causes aging (in part) or whether aging itself causes the decrease in melatonin. There is evidence from a variety of sources that “decreasing melatonin levels in your aging body may not be a consequence of growing older. Rather it may contribute to the aging process. It appears that by supplementing melatonin levels we may be able to extend our youth by more than 10 years,” (pg.2). Several studies have shown that the pineal gland appears to be the internal biological clock that controls aging. Melatonin may work in another way to slow the process of aging. As a powerful antioxidant it can slow the damage that appears to exacerbate more than 60 degenerative diseases including cataracts, heart disease, cancer, stroke, Alzheimer´s Disease, Parkinson´s Disease, rheumatoid arthritis and more. Melatonin is an efficient antioxidant because it works in all areas of the body and on all cellular types (even the brain), unlike many other antioxidants which are selective in their properties. Melatonin is also one of the safest antioxidants because of its lack of toxicity. Melatonin slows digestion, heart rate, blood pressure, body temperature, and more. It may not be surprising that it also slows aging. One of the best ways to promote a healthy melatonin response at night is to receive a dose of strong sunlight during the day. As people age they are less prone to go outside in the sunshine. This disrupts the body´s melatonin cycle. A Sunshine Room can be a great way of easily getting the sunshine your body needs.

Source: Melatonin, Russel J. Reiter and Jo Robinson; Stay Young the Melatonin Way, Steven Bock and Michael Boyette.

Condition Alzheimer´s Disease (AD)

Summary: Natural light can minimize some of the effects of Alzheimer´s Disease, including sleeplessness at night, physical inactivity during the day, lack of ability to regulate body temperature and related symptoms associated with the disease. Alzheimer´s patients exposed to high levels of light during the day (especially during the morning hours) slept better at night and were up less. They slept less during daytime hours and were physically more active during the daytime. They were also able to regulate their body temperature significantly better than persons who did not get regular doses of light, thereby avoiding abnormal body temperature fluctuations commonly seen in Alzheimer´s patients. In addition to regulating certain biorhythms, natural sunlight on the skin causes the body to produce vitamin D3. Vitamin D3 synthesis from natural sunlight is the single largest source of vitamin D3 for the body. And it has been noted that vitamin D3 may play a very protective role in both memory performance (De Viragh et al, 1992) as well as neurodegeneration associated with Alzheimer´s Disease (Sutherland et al, 1992).The biological basis behind Alzheimer´s Disease and supplementing additional sunlight for the Alzheimer´s patient is that the disease process of Alzheimer´s damages a part of the brain known as the Suprachiasmatic Nucleusor (SCN). This part of the brain uses light signals from the eyes to control the body clock and circadian rhythms. Thus it is essential to the Alzheimer´s patient as brain damage progresses that light be supplemented on what is commonly found in most indoor environments. It may also be noted that normal sunlight is far stronger and thus more effective than any of the artificial sun lamps on the market. 

Source: Biological Psychiatry, 1997 May 1;41(9):955-963; Acta Psychiatr Scand 1994 Jan;89(1):1-7; Neurobiology of Aging 1997;18(1):105-9; Journal of Geriatric Psychology and Neurology 1997;10(2):58-62; American Journal of Psychiatry 1992 Aug;149(8):1028-32; Alzheimer´s Disease and Associated Disorders 1997; 11(3):175-8; Sleep 1997; 20(1): 18-23; Prog Brain Responses 1992 ;93:151-162; International Psychogeriatrics 1996; 8 Suppl 3:245-52;discussion 269-72; Schweiz Rundsch Med Prax 1997; 86(35):1343-9; Proc National Academy of Sci USA 1992 Aug 1; 89(15):7090-94; Designing for Alzheimer´s Disease: Strategies for Creating Better Care Environments,” Elisabeth C. Brawley, 1997, John Wiley & Sons Publishers, NY, NY 10158.

Condition: Breast Cancer

Summary: Moderate exposure to sunlight is linked to a decreased risk for breast cancer. In addition, because older women are more prone to breast cancer than younger women, they were also the ones most likely to benefit from the positive effects of sunshine. “New studies indicate that vitamin D, a nutrient made by the skin during exposure to sunlight, can lower the risk of breast cancer by 30 percent to 40 percent and perhaps even more” (The On-Line National/World). Doctors believe this is because the body produces vitamin D with exposure to sunlight and vitamin D is believed to lower the risk of breast cancer. About 15 minutes per day in the sun should be sufficient to receive the preventive effects. One need not stay in the sun long enough to tan and it is important to stress that moderate exposure is all that is needed to prevent breast cancer and avoid premature skin aging as well as skin cancer.

Source: Sunlight,” Health Watch - A Public Service of the Office of News and Publications & the Library at UT Southwestern Medical Center at Dallas, TX; The On-line National/ World. The Associated Press (1997), Moderate Sun Exposure Might Lower Risk of Breast Cancer,” USA Today (11/03/97), Sun May Prevent Breast Cancer? Steven J. Milloy; Research Communications in Chemical Pathology and Pharmacology (Feb 94; Apr 94); Breast Cancer Research and Development (Feb 94).

Condition: Calcium Absorption

Summary: The main source of calciforal (vitamin D3) for the body is gained from exposure to natural sunlight. Supplements help, but are often not absorbed fully. Vitamin D3 is essential for the absorption of calcium and phosphorus. The study compared calcium absorption under two different lighting systems -- one which included natural sunlight, and other which did not. The study found that calcium absorption increased 15% under full spectrum light (natural sunlight). It also noted that calcium absorption decreased 25% under standard lights. 

Source: H.M. Hodkinson, B.R. Stanton and P. Round et al., Sunlight, Vitamin D and Osteomalacia in the Elderly, Lancet 1(April 28, 1973): p. 910; Neer, R.M. (1985). “Environmental Light: Effects of Vitamin D Synthesis and Calcium Metabolism in Humans.” R.J. Wurtman, M.J. Bohemia & J.T. Potts, Jr., “The Medical Effects of Light” Annuals of the New York Academy of Sciences, V. 453, New York: The New York Academy of Sciences, 14-20.

Condition: Circadian Rhythms

Summary: Circadian rhythms are normal biological factors (such as body temperature, sleep/wake schedule and hormones) that cycle on a regular pattern. Many circadian rhythms are disrupted by one´s normal light /dark schedule. Melatonin is one hormone (secreted by the pineal gland) which cycles on a 24 hour basis. Melatonin is believed to assert a coordinating or regulatory effect over a number of other circadian cycles\rhythms. Melatonin itself has sedative qualities and helps reduce anxiety, panic disorders, and migraines, and induces sleep. In addition melatonin plays an integral function in healthy immune system functioning. Melatonin production goes up dramatically during prolonged periods of darkness and is inhibited during periods of light. A strong high-low cycle is good. And a weak cycle caused by low levels of light during the day may cause insomnia, irritability, and other disorders. With regular sunlight, the cycle of melatonin will regulate within a few days. This in turn will help regulate other circadian cycles, improving one´s sleep, and more. Back to top

Source: R.M. Allen and T.K. Cureton Effects of Ultraviolet Radiation on Physical Fitness, Archives of Physical Medicine (Urban, IL: October 1945): p. 641-44; Lamberg Lynne, Body Rhythms: Chronobiology and Peak Performance, Ne, Ne:William Morrow, 1994; “Bright Light Fights Winter Blues,” USA Today Feb 94, Vol. 122, i. 2585, p.15; Harvard Mental Health Letter, Mar 95, Vol. 11Issue9, p.5; Women´s Sports & Fitness, Beating the Winter Blahs, Dec 93, vol.15, i.8, p.29.

Condition: Depression (see also, Seasonal Affective Disorder”)

Summary: While everyone experiences mild symptoms of depression from time to time, chronic (long-term) feelings such as guilt, anxiety, despair, misery, normal tasks becoming increasingly frustrating and difficult, irritability, hopelessness and loss of libido, could be symptoms of a larger, more serious disorder such as Seasonal Affective Disorder. See “Seasonal Affective Disorder” below. Back to top

Source: Journal of the American Medical Association, Light Therapy in Seasonal Affective Disorder is Independent of Time of Day or Circadian Rhythm, 2/2/94, vol.271, issue 5, p330i.

Condition: Pre-Menstrual Syndrome (PMS)

Summary: Exposure to both natural sunlight and artificial bright light created significant reductions in pre-menstrual syndromes including depression, mood swings, irritability, physical discomfort, and social withdrawal (possibly related to reduction of depression). Research from the University of California in San Diego shows that bright natural light is effective in treating depression associated with PMS. Studies have shown that women who experience significant PMS symptoms produce less melatonin than women who don´t (especially during the week prior to the onset of PMS symptoms). These and other findings have resulted in a melatonin-based treatment for PMS. Melatonin during the luteal phase of the menstruation cycle leads to a substantial reduction of PMS symptoms and in some cases may cause a complete disappearance of symptoms. To preserve your natural supply of melatonin, increase your exposure to sunlight, spending at least an hour a day in natural sunshine. Morning sunshine appears to be most effective in maintaining healthy levels of melatonin.Back to top

Source: American Journal of Psychiatry, June 1987 v144(6) p762-766; American Journal of Psychiatry, Sept 1989 v146(9) p1215-1217; Ladies´ Home Journal, PMS: A Glimmer of Hope?, Aug 94, vol.111, i.8, p.64; Melatonin, Russel J. Etier, Ph.D.; American Journal of Psychiatry, Treatment of a Patient with Seasonal Pre-menstrual Syndrome, Jun 1987 v.144(6) p.762-766; American Journal of Psychiatry, Morning Versus Evening Bright Light Treatment of Late Luteal Phase Dysphoric Disorder (i.e. PMS), Sep 1989, v.146(9) p.1215-1217; Body Rhythms: Chronobiology and Peak Performance, Lynne Lamberg, NY, NY: William Morrow, 1994.

Condition: Industrial Accidents

Summary: Enhanced light levels improve employee performance, especially when the employees make heavy use of their eyes alone or eyes-hands. A high light level during the day not only helps employees to see better, reducing accidents, but also helps employees to sleep better at night, resulting in higher levels of alertness. Evidence shows that the reverse also works for third shift workers exposed to bright lights (i.e., they experience an increase in alertness, performance and quality of daytime sleep).Back to top

Source: New England Journal of Medicine, “Exposure to Bright Light and Darkness to Treat Physiologic Maladaptation to Night Work,” 1990 v322 p1253-1259; Journal of Biological Rhythms, 1995 June; 10(2):135-147; Grinna et al (2000). Effects of Lighting on Health in the Workplace, A paper for the Lighting Research Center; Aston, S.M. & Bellchambers, H.E. (1969), “Illumination, Colour Rendering and Visual Clarity.” Lighting Research and Technology, (1) 259-261; How to Boost Your Brain Power, Roger Yepsen: Rodale Press, 1987.

Condition: Lethargy /Fatigue (also see Seasonal Affective Disorder”)

Summary: That feeling of tiredness catches up with everyone at some point. However, chronic lethargy or fatigue may be a symptom of a bigger problem such as Seasonal Affective Disorder when it comes to the point that it interferes with daily living (such as canceling appointments, missing work and avoiding pleasurable activities). See “Seasonal Affective Disorder” below.Back to top

Source: Article, Melatonin: The ‘Rest and Recuperate´ Hormone, Laurie Lee, 1999; Lamberg, Lynne, Body Rhythms: Chronobiology and Peak Performance, NY, NY: William Morrow, 1994.

Condition: Longevity (also see “Aging”)

Summary: One study by John Ott, Ph.D. indicates the importance of having balanced high quality light. A number of other studies also show that not just quantity, but quality, of light is important for health and a good sense of “well-being.” In the study by Dr. Ott, identical strains of mice were placed in otherwise identical environments with the only changes being the type of light they were exposed to.

  • Under pink fluorescent light the mice lived an average of 7.5 months.
  • Under cool white fluorescent light (the type typically used in most office environments) the mice lived an average of 8.2 months
  • Under full spectrum fluorescents with balanced trace ultraviolet (considered a high quality light) they lived an average of 15.6 months
  • Under natural sunlight the mice lived an average of 16.1 months. Back to top

Source: Maas, J.B., Jayson, J.K. & Kleiber, D.A. (1974). “Quality of Light is Important -- Not Just Quantity.” American School and University, 46(12),31; Ozaki, Y. & Wurtman, R.J. (1979). Spectral Power Distribution of Light Sources Affects Growth and Development of Rats. Photochemistry and Photobiology, 29,339-341; Wurtman, R.J. & Neer, R.M. (1970, February 12). “Good Light and Bad,” The New England Journal of Medicine, 282(7); Wurtman, R.J. (1975). “The Effects of Light on Man and Other Mammals,” Annual Review of Physiology, v.37.

Condition: Overeating (also see Seasonal Affective Disorder)

Overeating (usually carbohydrate craving), especially overeating during the winter months, is often a symptom of Seasonal Affective Disorder (SAD). While some weight gain (resulting from overeating) is normal during winter months, many times it can be improved with exposure to natural sunlight. Sunlight in the winter is less intense than it is during summer months. Longer periods of sun exposure may be needed in the winter to combat overeating (carbohydrate cravings) than may be needed in summer.Back to top.

Source: Women´s Sports & Fitness, Beating the Winter Blahs, Dec 93, Vol. 15, Issue 8, p.29; Tufts University Diet and Nutrition Letter, Shedding Dietary Light on Seasonal Affective Disorder, Mar 94, vol.12, issue 1, p1; Sunbox (11/99), SAD and Light Therapy, a paper by Michael A. Ferenczi, B.Sc., Ph.D.

Condition: Psoriasis

Summary: Ultra-violet light (which is found in full-spectrum sunlight) is regularly prescribed by physicians to reduce symptoms of psoriasis. Natural sunlight can significantly improve psoriasis as well. Interestingly, vitamin D3 cream is also prescribed to treat psoriasis (topically) and vitamin D3 is also produced naturally in the body by exposure to sunlight. In fact approximately 90% of the body´s stores of vitamin D3 come from exposure to sunlight and not through diet. The effects of sunlight on psoriasis are two-fold: (1) the ultra-violet light (UVB component) itself inhibits psoriasis and (2) the increased production of vitamin D inhibits psoriasis. Many studies have shown that moderate sunlight such as that received through normal use of a sunroom will not speed premature aging of the skin and may help improve a variety of specific ills, not to mention a general sense of well-being. Back to top

Source: Scientifically Proven Treatments for Psoriasis, A Paper from the National Psoriasis Foundation; University of Texas-Houston Lifetime Health Letter, “Let it Shine,” March 28, 1995; New England Journal of Medicine “Photochemotherapy of Psoriasis with Oral Methoxsalen and Long-Wave Ultraviolet Light,” 1974, v.291, p.1207-1211; Journal of American Academy of Dermatology, “Recent Advances in the Treatment of Psoriasis,” 1983, v.8, p.311-321.

Condition: Seasonal Affective Disorder (SAD), also Winter Depression, Winter Blues

Summary: Most people experience mild symptoms in the winter such as eating and sleeping more, a dislike of dark mornings and short days, sleeping but not feeling refreshed in the winter and family problems. Mild seasonal symptoms such as these are normal. However, when they become disruptive to normal daily life, the person is said to have “Seasonal Affective Disorder” or SAD. Studies have shown that persons with SAD do not have normal levels of melatonin in their blood. SAD tends to affect elderly persons more than younger persons simply because they tend to be indoors more of the time than younger persons. Regular doses of natural sunlight can restore normal melatonin levels and normal patterns of melatonin secretion, thereby improving mood (and mood swings), depression, and a variety of other disorders related to SAD. Full-spectrum light sends nerve signals from the retinas to the pineal gland in the brain (the source of melatonin production). Sunlight inhibits melatonin production and darkness dramatically increases melatonin levels. The brain interprets normal indoor light levels as “darkness.” Proper melatonin levels are a balance. In order to get a strong melatonin response at night, it´s necessary to shut off melatonin production during the day. One of the best ways to do this is through exposure to natural sunlight.

Seasonal Affective Disorder isn´t just something that happens in the winter. A lack of sunlight exposure during spring and summer can also produce SAD during the spring and summer. The good news is that SAD is easily and economically treated through exposure to sunshine. With the public becoming more and more aware of SAD, the question arises as to the best way to deal with its symptoms. Other than making it a point to get natural sunshine on a regular basis, other options include bringing natural sunshine indoors through the use of sunrooms, glass rooms, and skylights. The benefit of these types of glass-enclosed rooms is that one can still get all the healthy benefits of good quality sunshine even on days when the weather isn´t cooperating. A good dose of sunshine may help reduce feelings of sadness and/or depression, feelings of fatigue, tiredness, lethargy, difficulty in concentrating, reduce carbohydrate or sugar cravings, improve sleep, improve productivity (including employee productivity), reduce irritability, improve student scholastic performance, reduce your chances of certain types of cancer such as breast, colon and prostate, maintain healthy strong bones, prevent osteoporosis and much more! Back to top

Source: Winter blues: Treatment for SAD (Norm Rosenthal); Tufts University Diet & Nutrition Letter, “Beats the Daylight Out of Me,” Mar 94, vol.12, issue 1, p1; University of California at Berkeley Wellness Letter, “Festive Malaise,” Dec 93, vol.10, issue 3, p7; Harvard Mental Health Letter, “Season, Sex, and Psychiatric Symptoms,” Aug 94, vol.11 issue 2, p7; Journal of American Medical Association, “Diagnosis and Treatment of Seasonal Affective Disorder; 12/8/93, vol.270, issue 22, p2717; Journal of the American Medical Association, “Light Therapy in Seasonal Affective Disorder is Independent of Time of Day or Circadian Rhythms,” 2/2/94, vol.271, issue 5, p.330i; Harvard Mental Health Letter, “Light and Biological Rhythms in Psychiatry,” Mar 95, vol.11, issue 9, p5; USA Today Magazine, ³Bright Light Fights Winter Blues,” Feb 94, vol.122, issue2585, p.15; “Winter Blues: Seasonal Affective Disorder and How to Overcome It” (1993), Dr. Norman Rosenthal.

Condition: Sleep Disorders (see also Seasonal Affective Disorder)

Summary: Sleeping problems, especially during fall and winter months, can often be attributed to Seasonal Affective Disorder. Sleep symptoms include: (1) sleeping and/or sleeping longer, but not feeling refreshed upon awakening, (2) difficulty waking up and/or getting out of bed, (3) needing a nap in the afternoon, (4) light sleeping (easily waking up) at night, (5) frequently being awake for long periods of time at night, and (6) difficulty falling asleep at night. Most if not all of these symptoms can be relieved by restoring healthy melatonin levels. And one of the best ways to restore melatonin to its optimal levels, especially at night, is to get strong sunshine during the day (especially in the morning). Back to top

Source: American Journal of Psychiatry 149:1028-32, 1992; Journal of Biological Rhythms, “Light Treatment for Sleep Disorders: Consensus Report. IV. Sleep Phase and Duration Disturbances,” Jun 95, v.10(2), p.135-147.

Condition: Vitamin D production

Summary: Vitamin D (the type made by the body is actually vitamin D3, also known as Cholecalciferol) is important to a variety of body processes. It is significant to note that human evolution included daily sunshine as the most critical factor involved in vitamin D production. Apparently humans have long needed sunshine on a daily basis. Vitamin D is important for the absorption of calcium and phosphates from our diet. Without vitamin D, calcium passes through the digestive system unused. Vitamin D has been shown to have a strong inhibitory effect on cell growth and is under evaluation as a potential chemotherapeutic in breast cancer, colon cancer and leukemia (Feldman et al., 1996 in DiaSorin, 2000). Vitamin D deficiency may be a risk factor in prostate cancer as rates of prostate cancer are higher in northern latitudes where overall people get less sunlight (Hanchette and Schwartz, 1992 in DiaSorin, 2000). Vitamin D also boosts memory performance and increases neuron connections in patients with Alzheimer´s disease (De Viragh et al., 1992 in DiaSorin, 2000). Back to top

Source: Neer, R.M. (1975). “The Evolutionary Significance of Vitamin D, Skin Pigment and Ultraviolet Light,” American Journal of Physical Anthropology, 43(3), 409-416; “Why is Vitamin D Important?” (1997, 1998, 1999, 2000). DiaSorin, Inc., USA


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