Sun, Inflammation and Aging Skin
Inflammation caused by long-term exposure to sunlight hastens the damage of aging in skin, much as it does in many other tissues and systems in the body. From Science News: "Older skin cells turned up production of enzymes called proteases that break down collagen and elastin, proteins that give skin its spring and structure ... As collagen breaks down, skin collapses into wrinkles. ... It's the equivalent of taking the air out of a balloon. The tension goes out of it, and it begins to sag and fold in on itself. ... Inflammation also sets off other skin-damaging processes, such as inhibiting skin's regenerative abilities and changing fatty acid and cholesterol metabolism, which lead to erosion of the protective barrier that holds in moisture. ... sun exposure hastens "this chronic march down the calendar." ... Exposure to ultraviolet radiation from the sun increases inflammation, speeding the aging process."
Link: http://www.sciencenews.org/articles/20080301/note17.asp