The Negative Effects of UV Light on the Skin

UV exposure can age the skin, and there are many other negative health effects that can develop from excessive sunlight exposure.

Studies show that the highest period of exposure normally occurs between the ages of 41 and 59. It's a myth that the average person gets most of their ultraviolet (Sun) exposure before they're 18, so it's important to understand the risks and consequences of UV exposure.

Photo-aging and Collagen Degradation

There are two types of ultraviolet (UV) rays: UVA and UVB. When the skin is exposed to the sun UVA rays penetrate deep into the dermis where they damage the collagen fibers that support the skin. The body reacts to this damage by producing an abnormal amount of elastin and enzymes called metalloproteinases. These enzymes further degrade collagen levels resulting in incorrectly rebuilt skin. Daily UVA exposure causes this process to repeat itself regularly. Over time this incorrectly rebuilt skin begins to form fine lines and wrinkles, and the degraded collagen leads to leathery-looking skin.


When the skin is repeatedly exposed to UVA and UVB rays hyperpigmentation spots begin to appear, the most common of which are unwanted age spots, or sun spots. These spots can be found anywhere on the body that is exposed to sun, but they are most commonly found on the hands, arms, and face. In men, they are also often found on the back. Fortunately there are some available treatments including skin lightening creams and lasers.


The immune system is the body’s defense mechanism against infections and cellular changes (like cancers). Studies have shown that exposure to UV radiation at levels that exist in our environment can change the activity and distribution of cells that are responsible for letting the body know it must start fighting against infection (immune response). This means that exposure to the sun may increase the risk of infections caused by bacteria, viruses, parasites or fungi. There is also evidence that high ultraviolet radiation levels may limit the efficacy of vaccines. This is especially notable in countries of the developing world.

Skin Cancer

Exposure to UV radiation from both UVA and UVB light can cause damage to the DNA in skin cells and may even cause mutation of these cells. This may develop from long term sun exposure or short, intense periods of sun exposure (sun burn). The actual development of skin cancer can occur many years after the original cell mutation.

Keeping Your Skin Healthy

In addition to aging, skin exposure to sun rays can result in a host of long-term medical issues. The good news is that preventing this is simple: minimize your exposure to ultraviolet light. Wear sunscreen with a high sun protection factor (SPF), avoid being out in the sun during peak hours (10 am to 2 pm) and wear a wide-brim hat and protective clothing whenever possible.

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