Brandon McCulla and Julie Fazio of Cranberry Township soak up some sun recently at the Community Waterpark in North Boundary Park. Experts say too much exposure to the sun's ultraviolet rays can lead to cancer and other maladies.

While there are no substitutes for long sleeve shirts and wide-brimmed hats to reduce sun burn, many sunbathers will opt for more comfortable protection against harmful solar rays this summer.

Sunscreen has been an option for more than 70 years, but it is a product that has often been underused.

Sun protection factors (SPF) — a rating of how well a product blocks the sun's rays — have steadily increased over time.

Many of today's sunscreens boast SPFs above 50, leading many consumers to believe such products will provide all day protection from sunlight.

However, according to Mike Nanni, a pharmacist at Butler Rite Aid on Main Street, sunscreen should be reapplied at least every two hours, regardless of the SPF.

"People think using a larger SPF means they don't have to apply sunscreen nearly as often," Nanni said.

The SPF rating is most important when considering a person's skin type: The fairer a person's skin, the higher the SPF they should use, Nanni said.

Depending on a person's degree of physical activity, sunscreen may have to be reapplied every hour. Nanni recommends using water-resistant brands, particularly those that are oil or cream products.

These products allow a sun bather to spread sunscreen evenly over all exposed skin, but spray-on sunscreens waste the product and at times also miss key parts of the body, according to Nanni.

Another factor to consider when buying sunscreen is whether the brand blocks both ultraviolet A and ultraviolet B radiation.

While UVB radiation is the most damaging to the human body, it is significantly less common than UVA radiation, the type of light that tans the skin.

According to a figure from the Skin Cancer Foundation website, UVA rays account for 95 percent of ultraviolet radiation that reaches the Earth's surface.

UVA radiation has been linked with premature skin aging, eye damage, certain skin cancers and suppression of the immune system, according to the website.

Nanni said there are often cheaper sunscreens that are just as effective as name-brand products.

"Many people can look for generic alternatives; store brands should be trusted," Nanni said. "There are many options and a big variety of price options."

For parents worried about their children having allergic reactions to traditional sunscreens, there are a number of metal-based alternatives.

Sunscreens based on compounds such as titanium oxide are unlikely to cause allergic reactions, but can be slightly more expensive than other products.

Zinc-based predecessors of modern metal-based sunscreens were known to leave white marks. Now metal-based sunscreens dry clear.

"You don't have to make yourself have a white nose to use things like this," Nanni said.

Regardless of the type of sunscreen bought, it needs to be applied seven to 10 minutes before going outside, Nanni said.

In 2007 the Food and Drug Administration proposed several updates to its guidelines on sunscreen, which were created in 1978. Updates would call for more detailed product labels, including a four-star rating system that would rank a product's effectiveness in blocking UVA radiation.

The FDA also hopes to prevent companies from printing labels that claim SPFs of 50 or higher, saying those claims cannot be reliably substantiated.