subject: How Does The Sun Affect My Aging? [print this page] Sunlight has a significant effect on the skin and its aging process. It is the primary source of pre-mature aging. Damage from sunlight exposure is cumulative and, in part, irreversible. Many aging issues seen in skin over time are actually due to sunlight exposure.
Types of Ultraviolet Radiation
The aging effect is due to the ultraviolet light that is emitted from the sun. There are three different wavelengths of UV radiation. The first, UVC, is absorbed by the ozone layer and does not affect the skin. The second, UVA, was once thought to have little effect on the skin. However, recent studies have shown that UVA rays are more harmful that originally thought. These rays are constant, intense and are not filtered by glass. The third, UVB, has long been known to cause damage to the skin. UVB rays affect the outer layer of skin and are the cause of sunburns.
How UVA and UVB Affects Aging
Collagen breakdown is thought to be the major cause of pre-mature signs of aging. Collagen is the natural fiber that gives the skins its firmness and elasticity. As people age, the fibers begin to break down. This causes wrinkles and sagging skin. With consistent sun exposure over time, the harmful rays damage the dermis of the skin. This causes the collagen to begin to break down at a faster rate than normal, aging the skin beyond its years.
Free Radicals
In addition to breaking down and weakening collagen fibers, UV radiation is a major source of free radicals. A free radical is an oxygen molecule that has only one electron instead of two. The molecule seeks out other molecules to steal electrons from. This causes the second molecule to continue the process of seeking out a second electron. This cycle damages cell function and can even change genetic material.
Weakened Immune System
Sunlight can cause chemicals in the skin to be released that suppress the immune system. The result is an increase in the risk of skin cancer. It also inhibits the bodys natural ability to repair itself and to fight off free radicals.
Changes in Texture and Color
Sun exposure can cause the skin to thicken in certain areas such as the neck. It can also cause thinning of the skin, which leads to fine lines, bruising and tearing. Pigment changes are also common. Age spots, or liver spots, are a result of damage to the cells that produce melanin. The damage causes the cells to become enlarged and dark in color. It used to be thought that these spots happened with age, but it is now known that the cause is damage from the sun.
