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BENNINGTON — It is no secret that radiation, even in small doses, can be toxic. And yet, studies show that more than a third of adults let themselves be burned annually by the dangerous ultraviolet radiation that sunlight delivers. Worse, we allow two thirds of the nation’s children to sustain this injury every year. The damage done to a sunburn victim’s skin causes pain and malaise. It also promotes long lasting skin and eye damage. Good protection strategies exist, fortunately, but they need to be implemented to work.

Sunburn, technically called acute cutaneous inflammation syndrome, is caused by over exposure by the skin to UV radiation. The sun is the most common source of this damaging energy, but it is also emitted by tanning beds, sun lamps, and welding arcs. It directly damages the DNA of the skin, resulting in a massive release of inflammatory substances from the cutaneous immune system within one hour of excess sunning. Within 2 hours, microscopic examination of burned skin shows dying and dead cells.

Sunlight contains abundant ultraviolet radiation of both the “A” and the “B” types. While both of these contribute to premature wrinkles and cancer, it is the higher-energy UV-B that causes the malady commonly known as sunburn. Interestingly, UV-A levels are relatively constant over time and location, while many factors influence UV-B levels. For instance more UV-B rays reach the planet between 10 a.m. – 4 p.m. UV-B is filtered by the atmosphere, so folks at higher altitudes get a greater exposure than those at sea level. Snow and ice are capable of radiating over 80 percent of the ultraviolet rays that lad on them; sand only about 20 percent.

Acute sunburn can be extremely painful and is associated with dizziness, headache, and fever. While anti-inflammatory agents like ibuprofen can improve comfort, nothing reduces the intensity or duration of the actual tissue destruction. As a result, of the DNA damage, there subsequently is an increased risk of three types of skin cancer (melanoma, squamous and basal cell) as well as the common eye malady, cataracts and macular degeneration. One’s health and quality of life is definitely improved by avoiding too much sun.

Fortunately, there are some very successful strategies to prevent sunburn. Limiting outdoor activity between 10 a.m. – 4 p.m. is profoundly helpful. Note that this refers to all days, as UV radiation can penetrate cloud cover. But that is a sad option for most of us, so we need to turn to clothing and chemicals to help. Hats and tightly woven fabrics provide marked protection from UV radiation burns. UV-blocking sunglasses reduce damage to our eyes. And, of course, there is sunscreen.

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It is quantity, not quality, that predicts how well your sunscreen works for you. Most of these products work by absorbing the UV rays themselves so that your skin does not. Note that SPF 30 offers only 5 percent more protection than SPF 15, and there is no proven additional benefit for screens claiming SPF 45 or higher. To get any truly effective protection, however, experts note at least one full ounce (about a shot glass full) of sunscreen must be applied. And the optimal time to apply is 20 – 30 minutes before sun exposure. The product should be reapplied after vigorous exercise or extensive swimming or if several hours have passed.

These chemical sunscreens solely decrease the B-type radiation that reaches our skin, so they markedly decrease the likelihood of burn but do not fully erase risk of premature aging and cancer, because UV-A rays are unaffected. Only products described as sunblock, that actually block or reflect the sun’s radiant energy, are able to divert both UV-A and UV-B from our bodies. Zinc oxide or titanium oxide are the main ingredients of these products.

Some of us are hesitant to limit time in the sun due to vitamin D concerns, for this vitamin is produced in our skin cells when they are stimulated by UV rays. But the body’s ability to produce vitamin D this way is highly variable, and many sunworshippers still have insufficient levels. The medically advised method to assure adequate vitamin D levels is now oral supplementation.

To summarize, too much sun exposure causes immediate pain and long-term damage to skin and eyes. Good timing, intelligent clothing, and sufficient use of sunscreen can go a long way to limiting its destructive effect on our bodies. Please, folks, enjoy your summer, but carefully!

Patrice Thornton, MD, is a primary care physician at SVMC Northshire Campus, part of Southwestern Vermont Medical Center and Southwestern Vermont Health Care in Bennington.


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