'Aging' signs caused by sun The most dangerous part of the year for sun damage to your skin is not necessarily the hottest part of the year, according to a leading authority on the dangers of excessive sun exposure. Dr. Myra Barker, vice president of research and development for Mary Kay Cosmetics, Inc., explains that sun exposure reaches a danger peak for ultraviolet B radiation (the type generally blamed for most skin damage) on June 21 in the Northern Hemisphere, "but that can be very misleading," she says. "The dangers begin building up in April and May. You may think more about it in August when the temperatures top 100 degrees, but the danger of skin damage actually peaked two months earlier," according to Dr. Barker. The dangers of excessive exposure to the sun are many. Some signs we generally consider part of the normal aging process are not really from aging as much as from being in the sun, whether the exposure was planned or not. "Wrinkling is one form of skin damage," Dr. Barker says. "It is caused caus-ed by permanent changes in the dermis, der-mis, the underlying layer of skin. "There's nothing that can be done to reverse it other than plastic surgery once it happens. Sun damage is largely cumulative and irreversible," she says. The most serious consequence of sun damage, however, is skin cancer. Dr. Barker says an estimated 300,000 persons per-sons this year will be treated for skin cancer, and that about 5,000 of these persons will die. "Skin cancer is one of the most common forms of the disease-in disease-in this country," she says, "and the sad part is that most of these cases are un- necessary. "It is strictly a question of our personal per-sonal habits and of the choice we make for ourselves in terms of sun exposure," ex-posure," she says. Dr. Barker also cautions against thinking a tan is "healthy." "A tan only looks health," she says. "One of the most misunderstood conceptions about sunlight is that a tan is protective and once you've tanned, you no longer need a sunscreen." "This is not true. Tanning will help prevent a sunburn, but tanning increases in-creases your risk of skin aging and skin cancer. It is not protective against skin aging. It is not protective against skin cancer." Dr. Barker also offers these thoughts on related subjects: Sunburning: "A sunburn is not a simple phenomenon that is temporary, hurts a while and goes away. It is a permanent per-manent form of skin damage and there is evidence that severe sunburning early ear-ly in life tends to increase the chance of skin cancer later." Freckling: "People who freckle are more likely to develop skin cancer than other people because freckling is a sign the skin cannot adequately pigment itself evenly. If you have children who freckle, please, please teach them to wear a sunscreen." Acne: "Many people believe acne is lessened by sun exposure. Sometimes this is so, but there are many people whose acne doesn't improve, it gets worse. No one knows exactly why this is so and it's difficult to predict what will happen to any one person." -Spotting: "Those brown spots you see on the back of the hands or face that we used to call 'liver spots' don't have anything at all to do with your liver. It has to do with sun exposure." Fortunately, there are two things the average person can do to limit damage from the sun. First, don't expose yourself to direct sunlight for extended periods of time. Once the damage is done. Dr. Barker says, there is no way to undo it. Second, if you are going to be in the sun, even for short periods of time, use a sunscreen with a high SPF (Sun Protection Pro-tection Factor). The higher the SPF number, the greater amount of ultraviolet radiation it will absorb before your skin is damaged. Use of a high SPF sunscreen is particularly important im-portant for persons who sunburn easily. "And," Dr. Barker adds, "apply the sunscreen very' liberally seven to 15 minutes before you go out, and reapply it often. Don't wait until you start to redden before putting it on. The protection protec-tion you will receive takes awhile to begin working."