Wrinkles, or rhytids, are lines, creases, and furrows in the skin. They develop as a normal part of the aging process as skin becomes thinner, dryer, slower to renew and repair itself, and is drawn downward by the pull of gravity. In women, hormonal changes associated with menopause further contribute to the development of wrinkles. The number and severity of wrinkles can be affected by lifestyle factors including sun exposure, smoking, and even repeated facial movements, which is why they're especially prominent on the face, especially around the eyes and mouth.
Over the course of a lifetime, skin is subjected to the impacts of aging, sun exposure, free radical damage, smoking, and repetitive movements of the facial muscles. All of these contribute to the development of wrinkles to varying degrees.
With age, the skin undergoes multiple changes that contribute to the development of wrinkles:
Repetitive facial movements, such as frowning, squinting, and smiling cause tiny facial muscles to contract. Over time, these muscles don't relax, they stay contracted; this, coupled with the pull of gravity, contributes to wrinkles. These vary from tiny lines that extend vertically from the upper lip (smoker's lines) to deep crevasses between the eyes (frown lines) to nasolabial folds, which extend from the side of the nose to the corner of the mouth (laugh lines).
Age-related skin changes that cause wrinkles are inevitable. Certain other contributing factors are not.
Exposure to the sun's ultraviolet (UV) rays, both UVA and UVB rays, accounts for 90% of premature skin aging, or what's called photoaging. The severity of skin damage caused by the sun is determined by total lifetime exposure to UV rayes as well as skin color (pigment): The darker a person's skin the more natural protection they have from the effects of radiation.
Exposure to the sun affects the layers of the skin in different ways. It damages collagen fibers in the dermis and elastin fibers begin to accumulate at abnormal levels. This accumulation causes enzymes called metalloproteinases to be produced in large quantities. Typically, metalloproteinases repair skin by producing collagen, but sun damage causes them to malfunction and actually break down collagen, leading to the formation of fibers called "solar scars." As the skin repeats this imperfect rebuilding process over and over again, wrinkles develop.
Free radicals are unstable oxygen molecules that alter the genetics of a cell and cause wrinkles and skin damage by activating the metalloproteinases that break down collagen. The smallest amounts of UV radiation, smoking, or exposure to air pollution can worsen this damage.
Smokers tend to experience premature wrinkles and their skin often appears dramatically older than that of people of the same age who do not smoke. Harmful chemicals in tobacco damage skin in a variety of ways, affecting elasticity, texture, color, and chemical makeup. One of these is by producing excess metalloproteinase.
In addition, the nicotine in cigarettes causes narrowing of the blood vessels in the outermost layers of skin, limiting the amount of blood, oxygen, and nutrients, such as vitamin A, that reach and nourish skin. The skin cells of smokers is slower to regenerate as well.
From fine lines to deep furrows, skin wrinkles are an inevitable part of aging. Some people embrace, or at least accept, crow's feet, smile lines, and so forth as emblems of a life well-lived. Others don't. If you fall in the latter camp, you're probably aware of the many anti-aging skin products designed to reduce the appearance of wrinkles. A better approach to dealing with these and other signs of aging, though, is to begin taking steps to prevent them while you're young. While most of the changes in skin that cause wrinkles can't be avoided. lifestyle practices such as unprotected sun exposure, smoking, eating a diet low in nutrients, and not staying hydrated all can contribute to the early onset of wrinkles. The healthier your lifestyle is overall, the better able you'll be to stave off wrinkles and other signs of aging.