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Published on June 09, 2020

Protect Yourself with Sunscreen

Applying sunscreen to young girl

Everyone knows that sunscreen should be on your must-pack list for the pool or beach.

But summer is not the only time you should protect your skin from sun exposure.

In fact, according to Janine Cooley, MD, a physician with EvergreenHealth Primary Care in Redmond, you should take steps to protect your skin every day, not just when you’re sunbathing or out in the sun for prolonged periods of time.

“Most people think of using sunscreen during the summer, but it’s an important weapon against skin cancer practically every day of the year,” says Dr. Cooley.

According to, about 90 percent of non-melanoma skin cancers and 65 percent of melanomas are associated with exposure to UV radiation from the sun.

Skin cancer is the most common form of cancer in the U.S., and one in five Americans will develop skin cancer in the course of a lifetime, says

Protecting against UVA and UVB

The sun has two types of ultraviolet (UV) rays: Long-wave rays called UVA and ultraviolet B shortwave rays, or UVB.

At one time, only UVB was thought to create a risk of skin cancer. Research in recent years, however, has revealed that UVA — while less intensive than UVB — can cause skin damage as well.

“I always recommend that my patients use a broad-spectrum sunscreen that is designed to protect you from both types of rays,” Dr. Cooley says.

Additionally, she gives patients the following guidelines about applying sunscreen:

  • Not one-and-done: Sunscreen should be applied every two hours and every time you get out of the water.
  • Shot glass full: One ounce of sunscreen—about the equivalent of a shot glass—is the amount that should be applied each time.
  • Be prepared: You should put on sunscreen about 15 to 20 minutes before you go out in the sun. The sunscreen needs time to form a protective film.
  • Age-sensitive: Sunscreen shouldn’t be used on babies under 6 months of age. There is concern that their skin will absorb the screen and react to its harsh chemical ingredients more readily than an older child's.
  • No sweat: FDA rules do away with "waterproof" and "sweat proof" labels on sunscreens, because such claims are impossible. Sunscreen manufacturers can claim products are water-resistant for either 40 or 80 minutes, depending upon test results.
  • Check the expiration date: While sunscreen can last for a long time, it’s important to check the expiration date. The active ingredients aren’t going to be effective after a certain time period. For best results, buy a new bottle each season or vacation.

Sun penetrates indoors, too

You may need to apply sunscreen even when you will be indoors.

UVA rays — known to be able to pass through windows — have been found to cause wrinkles, brown spots and sagging skin on the study participants who all worked indoors. According to the report, the side of the subjects' faces that was regularly closer to a window exhibited more signs of sun damage.

“If you are at home, work, commuting in the car, or in another situation where you’re still exposed to regular sunlight, you need to protect your skin, just like you would if you were going to sunbathe or be outside,” Dr. Cooley says.

Sunscreen or sunblock?

A lot of people think of sunscreen and sunblock as the same thing, but they actually are different.

“Sunscreen is made up of chemicals that diffuse the rays from the sun. It keeps most rays out but lets some in,” Dr. Cooley explains, “whereas block reflects the sun’s rays from the skin to block them from penetrating the skin.”

She says those with fair skin that burns easily may want to use more protective sunblock. Those with darker skin can use sunscreen.

The tips on sunscreen use listed above, however, apply to everyone. For more specific guidance on how to treat your skin type, visit

SPF: is higher better?

Dr. Cooley recommends an SPF, or Sun Protection Factor, of about 30.

SPF is a measure of UVB protection and the time it would take you to sunburn if you were not wearing sunscreen, as opposed to the time it would take with sunscreen on.

The difference between an SPF of 30 and higher ones is minimal, she says.

  • SPF 15 products block about 94% of UVB rays
  • SPF 30 products block 97% of UVB rays
  • SPF 45 products block about 98% of rays

“After 30, the higher the SPF doesn’t really change its effectiveness a great deal,” says Dr. Cooley. “The key is really to keep reapplying every two hours.”

The downside of sprays

Dr. Cooley also says that while most of her patients probably use sunscreen sprays, they aren’t as reliable as people think.

“Sprays are very popular because they dry faster and are easier to apply,” she explains. “But they have their limitations.”

The biggest limitation is inconsistent SPF performance. “It’s hard to know if you got the spray on evenly, which means you may not be getting adequate coverage all over your body. And if you’re on the beach where it’s often windy, you may not be getting it on you at all.”

Sunscreen cream not only gives more reliable performance but is also much more cost effective.

Is using sunscreen safe? What ingredients should I look for?

Choose oil-based creams with inorganic filters, like titanium dioxide and zinc oxide, over sunscreens with organic filters for infants and children, because they offer broad-spectrum protection and have minimal irritation. They are safer for sensitive skin and pose less risk of potential skin penetration.

Given recent news regarding the safety and long-terms effects of sunscreen, it is important to note that under real-life conditions, most people likely apply only 25 to 50 percent, or even less, of the maximal amount of sunscreen used for product testing, and do not always apply sunscreens every two hours.

Thus, until further data are available, recommendations for sunscreen use remain unchanged. For those concerned about systemic absorption of organic sunscreens, sunscreens that contain inorganic constituents (zinc oxide, titanium dioxide) can be recommended.

Sunscreen plus

Sunscreen is a must out in the sun. But it’s not enough.

If you plan to be out in the sun for a prolonged period of time—particularly between 10 a.m. and 4 p.m.—then you should also consider a hat, sunglasses, an umbrella and protective clothing.

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