Sunscreen 101: How to protect your skin from skin cancer and premature aging

July 6, 2021
family outside in the sun, learning how to protect their skin from sunburns.
Understanding how to protect skin when outdoors in Colorado will help prevent skin cancer and premature aging. Source: iStock.

Colorado, as many of us regularly brag to our out-of-state friends, has 300 days of sunshine. Those sunny days are one reason it’s a great state to enjoy outdoor activities such as hiking, biking, and skiing.

The one downside to these sunny days and outdoor activity opportunities is excessive exposure to the sun’s ultraviolet rays. Because of sun exposure at high altitudes, Colorado has the nation’s highest per-capita rate of skin cancer.

The good news is that you can reduce your risk of developing skin cancer without hiding inside all day, and it starts with how you protect your skin.

“Sunscreen is the best weapon we have against protecting our skin from ultraviolet radiation, which can lead to aging of the skin and skin cancer,” says Aly Barland, MD, UCHealth dermatologist at the UCHealth Longmont Clinic.

The when, where and how of applying sunscreen to protect your skin

Whenever you’re outside, and your skin is exposed, whether it’s cloudy and cold or hot and sunny, you should wear sunscreen, says Barland. “There are always ultraviolet rays that your skin’s receiving.”

She recommends not only covering all exposed skin with sunscreen but also, in some cases, covering skin with clothing, especially if you’re playing sports or doing some sort of outdoor activity.

An ounce of sunscreen, about a shot-glass size of sunscreen, is the amount needed for your entire body. Be sure to apply it about 20 minutes before sun exposure so it has time to dry. And the best way to apply it is to squeeze some lotion onto your hands and rub it directly on your skin.

“Usually, a cream or lotion is more effective than a spray because you may not be directly applying [the sunscreen] to your skin since some of it is aerosolized. You get a more even layer of sunscreen when you use a cream or lotion and apply it with your hands.”

Is mineral sunscreen or chemical sunscreen better?

The best sunscreen is the sunscreen that you use regularly. Whether it’s chemical sunscreen or mineral sunscreen, a spray sunscreen or sunscreen lotion, the type is not as important as the effort.

As for ingredients, Barland says, it’s a matter of preference when it comes to using a mineral sunscreen or a chemical sunscreen. For those with sensitive skin, or concerns about chemical ingredients, a mineral sunscreen would be the best sunscreen option. The only two mineral sunscreen ingredients available are zinc oxide and titanium dioxide. These ingredients sit on your skin as a shield against the sun’s ultraviolet rays. They are not absorbed into your skin or bloodstream.

Recent studies have found that chemical ingredients such as avobenzone and oxybenzone are absorbed into the skin and, subsequently, your bloodstream.  However, it’s not known at this time if those ingredients are harmful.

“We do not yet know the implications of chemical absorption and whether it is harmful,” says Barland. “We do know that skin cancer can be deadly. If people are hesitant about sunscreen use and these studies, they can stick to mineral sunscreens only.”

Is it necessary to reapply sunscreen?

Absolutely, it’s necessary to reapply sunscreen. Many people think that slathering on sunscreen once is fine. Not true. Sunscreen wears off, especially if you’re sweating or swimming. The general rule is to reapply every one to two hours if you’re going to be outside for a while, says Barland, because it becomes less effective over time and in the sun.

But, if you’re swimming, you should reapply as soon as you get out of the pool. “If you’ve been swimming or sweating, reapplying is important because water-resistant sunscreen is not waterproof, and it also washes off some in the water or with sweat.”

What SPF do I really need?

Barland recommends a sun protection factor, or SPF, of at least 30. SPF tells you how long the sun’s ultraviolet rays would take to cause damage to your skin. So, if you use an SPF 30 product, it would take 30 times longer to burn than if you weren’t wearing sunscreen.

The higher the SPF factor, the longer you’re protected, to a degree. For one, it’s only an accurate number if you apply the sunscreen as directed, meaning an ounce for your entire body and reapplying it regularly throughout the day.

“I generally recommend SPF 30 to 70. Beyond SPF 70, you’re probably not gaining much more in protective level,” says Barland.

For kids, do you need a children’s brand sunscreen?

Children under six months should not wear sunscreen. However, you should still protect them from the sun with protective clothing and shade. For children older than six months, any sunscreen will do. It does not need to be branded as a kids’ sunscreen.

Mineral sunscreen, though, maybe a better option for children. “For kids older than six months, any sunscreen is fine. But we do typically recommend sticking with a mineral sunscreen for kids because they tend to have more sensitive skin and mineral sunscreens are less irritating,” says Barland.

How else can I protect my skin from the sun?

In addition to sunscreen, you should wear a wide-brimmed hat, sunglasses and limit sun exposure between 10 am and 4 pm when the sun’s rays are the strongest. These, and other sun protection guidelines, should be followed year-round.

Obviously, when you’re skiing, you don’t have to cover your body with sunscreen. But, you should protect any exposed skin. “It’s important to remember that the sun is always present, no matter what season we’re in. You need to protect your skin throughout the year,” Barland says.

About the author

Joelle Klein is a Colorado-based freelance health and lifestyle writer. She regularly writes for UCHealth Today, Colorado Health & Wellness Magazine and Bottom Line Health. Her articles and blogs have appeared in 5280, Skiing, Fit Pregnancy, Pregnancy, the Denver Post, PBS Next Avenue, AARP, and the American Lung Association, among dozens of other health-related print and digital publications.
Joelle earned her bachelor’s degree in English at New York University and her master’s degree in journalism at the University of Colorado at Boulder. She is a member of the Association of Health Care Journalists (AHCJ) and American Society of Journalists and Authors (ASJA). Joelle lives in Denver with her husband and their two daughters. In her limited spare time, she enjoys cooking, reading, hiking, biking, camping, theater, travel, and spending quality time with her family.