Check Your SPF

According to the American Academy of Dermatology, about 1 in 5 Americans will be diagnosed with some form of skin cancer over lifetime. Sun exposure can cause damage to the skin, accelerating the aging process and leading to the development of cancer cells.

The first line of defense against overexposure to the sun’s rays is sunscreen. How can you choose the most effective sunscreen for your needs and when should you apply sunscreen for optimal benefit?

First, let’s take a look at the types of sun rays. The light from the sun travels in two different types of rays, harmless longer or radio waves and shorter dangerous waves such as UV rays. The longer of UV rays are known as UVA rays; shorter rays are known as UVB rays. Both types cause damage to the skin.

When you forego sunscreen during an afternoon at the beach or pool, you may get a sunburn, caused by UVB rays. UVA rays reach more deeply into the skin, causing damage. Either type of UV rays disrupts the skin’s regeneration and appearance.

Long-Term Sun Damage

Continuous exposure to UV rays puts the aging process into fast motion. Early sun exposure during childhood accelerates something known as the photoaging process, causing damage such as wrinkles and discoloration.

The skin does have the ability to heal itself. For example, the peeling that occurs with a bad sunburn sheds off skin cells damaged by the sun. However, the skin’s ability to self-repair is diminished. UV damage to the skin and connective tissue increases, which is why wrinkles and lines appear.

Skin Cancer

While the wrinkles, fine lines, and spots of sun damage are a nuisance, skin cancer is a significant health threat. Excessive sun exposure increases your risk for skin cancer, which is the most common form of cancer in the United States.

UV rays damage the DNA or genetic material. All cells grow and divide but the DNA damage can cause this process to happen in an uncontrolled way, leading to bundles of extra cells that result in either a lesion or a tumor, which can either be malignant or benign.

Skin cancer can be basal cell carcinoma, squamous cell carcinoma or melanoma, which is less common but more dangerous.


The best protection against sun damage and skin cancer include avoiding direct sun exposure between 10 am and 4 pm, avoiding tanning beds, and applying sunscreen on a daily basis, not only when you’re at the beach or pool.

The SPF factor of sunscreen relates to the amount of time you can spend in the sun before burning. For example, if you use an SPF factor of 15, it would take 15 times as long to burn as you would without any sunscreen.

What to Look For in a Sunscreen

Broad Spectrum Protection: These sunscreens protect against both UVA and UVB rays. Sunscreens that are not broad spectrum only provide protection from sunburn, not skin cancer or aging because they only provide protection from UVB rays. UVA rays are contribute to both premature aging and skin cancer.

SPF 30 or Higher: This number relates to the level of UVB protection. SPF 50 filters out about 98% of rays and SPF 100 filters out about 99%, though no sunscreen provides complete protection. Any sunscreen with an SPF of 15 or lower does not provide protection from skin aging or skin cancer.

Waterproof vs Water Resistant: Water resistant sunscreen can last either 40 or 80 minutes when swimming  or sweating. It’s best to reapply sunscreen every two hours or even more often when swimming or sweating, as well as when you towel off after swimming.

Check Expiration Date: Sunscreen used past the expiration date loses effectiveness.

The Bottom Line:

To minimize premature skin damage and risk for skin cancer, avoid direct sun exposure between 10 am and 4 pm. Do not use tanning beds and apply sunscreen each day. Look for broad spectrum formulas with SPF of at least 30 and be sure to apply often, all year round.