Scientific research has identified a variety of factors that affect extrinsic and intrinsic aging of the skin. Many of these factors are controllable by simply modifying your behavior and diet. This section covers ways to prevent skin aging, and the following sections cover ways to treat it.

Sunlight is the major cause of extrinsic skin aging and skin cancer. It damages collagen and elastin and can cause changes in cells that trigger cancer. Doctors call this type of skin aging photoaging, that is, aging produced by light.

Everyone is susceptible to it, even people with dark skin. Though more skin pigment reduces sun damage, the intensity of sunlight and cumulative exposure will eventually cause photoaging in people of all skin colors. Avoiding sun damage is the most effective thing you can do to prevent aging of your skin.

The majority of visible skin aging occurs in the face, because it is regularly exposed to the sun. If a person were able to avoid sun exposure their whole life, their face would have few wrinkles and discolorations, even in old age. Some old people who have had little sun exposure look remarkably youthful.

The body of a 60 year-old person who exercises regularly and eats right can look as good as that of an average 40 year-old; the same could be true of our faces if we avoided sun exposure. So if you want healthy skin, you need to stay out of the sun or cover up with clothes, a brimmed hat and a broad-spectrum UVA/UVB sunblock. This is very important for children too, because sun damage is cumulative.

Don't use tanning beds; they are little better than baking in the sun. If you go swimming, use a beach umbrella when you are out of the water. If you wear very light-weave clothing in the summer, you should apply sunblock underneath, because the fabric may only partially block the sunlight.

Wear good-quality UV-blocking sunglasses, since sunlight can damage your eyes and the delicate skin around them. Also ask your optician for UV-blocking lenses if you wear clear prescription glasses.

Sunblock Works

Sunblock is a true anti-aging product because it prevents sunlight from damaging your skin. However, older "suntan lotions" didn't do a very good job of blocking UV rays, so many middle-aged and older people have skin photodamage, even if they used these products in their youth.

Today there are all sorts of very effective sunblock products available from very light gels for daily use, to thick waterproof creams for swimming. (Avoid daily use of sunblocks containing alcohol, which isn't good for your skin.) Some makeup products now incorporate sunblock. Look for a sunblock that is labeled for both UVA and UVB solar radiation protection. (UVA and UVB refer to different wavelength ranges of ultraviolet light.)

It is best to buy brands that have an expiration date printed on the label or bottom of the bottle, since most sunblocks lose potency over time. Read the directions on the bottle. Most sunblocks require a number of minutes before they start working, and you need to reapply them after a certain period of time.

Some sunblocks may stain certain fabrics, so you should apply some to a similar scrap of cloth before wearing the sunblock with good clothes. If you are going to be in the sun for an hour or more, you should use sunblock with a sun protection factor (SPF) of at least 15. Higher values will allow you to stay in the sun longer, but they also expose your skin to higher concentrations of the various sunblock chemicals - some of which may irritate your skin.

SPF ratings are a measure of how long the sunblock lasts on your skin, not a measure of "blocking power." So higher SPF values are appropriate if you are going to be in the sun for many hours and don't want to apply more sunblock later. However, if you sweat a lot, you should apply more sunblock after an hour or two no matter what the SPF value.

If you wear makeup, try to find a product line that incorporates sunblock in its products or which has a chemically-compatible sunblock that you can apply under the other makeup products.