What You Need to Know About the Sun and Sunscreen

BY KRISTINA M. BRITTON, M.D.

With spring just around the corner, it is a great time to discuss the importance of sun protection. We all love the warmth of the sun on our skin and the sun is important to our overall health. Sunlight increases the levels of serotonin in our brain, resulting in more energy and an improved mood. Light therapy is a proven treatment for Seasonal Affective Disorder (SAD). The sun is also needed for our bodies to produce vitamin D. Vitamin D helps regulate calcium and phosphate in our body, which are essential for healthy bones, teeth and muscles. Vitamin D is also important for our immune system.

Despite all these benefits we get from the sun, it can also cause damage to the skin. Sunlight is composed of ultraviolet A (UVA) and ultraviolet B (UVB) wavelengths of light. UVA are longer wavelengths of light that can penetrate deeper into the skin, creating reactive oxygen species that can damage our DNA and cause skin cancer. UVB are shorter wavelengths of light that do not penetrate as deep but can cause sunburns, suppress the skin’s immune system, and can also damage DNA.

The sun does prematurely age our skin, resulting in wrinkles, sunspots, rough and dry skin. These changes in the skin are referred to as photoaging by dermatologists. People spend significant amounts of money to reverse the signs of aging. The global anti-aging market is greater than $62 billion U.S. dollars. The sun also suppresses the skin’s immune system and increases the risk of skin cancer. According to the American Academy of Dermatology (AAD) website, skin cancer is the most common cancer in the United States and that current estimates are that one in five Americans will develop skin cancer in their lifetime. It is estimated that approximately 9,500 people in the U.S. are diagnosed with skin cancer every day.

As with most things in life, sun exposure in moderation is important. Getting 15-30 minutes of sun exposure on the face, arms and hands three times a week is all that is required to maintain an adequate vitamin D level. However, this is dependent on skin type, age, time of day, season, latitude and cloud cover. If you eat a healthy, well-balanced diet, most people get enough vitamin D from their diet. People who live in northern climates tend to be vitamin D deficient as they are not getting enough sunlight through the colder months. If you do not suffer from a malabsorption disorder, it is recommended to get vitamin D from an oral supplement. Despite their advertising, tanning booths are not a good source of vitamin D. Tanning booth light bulbs emit UVA light and very little UVB light, which is the wavelength required to generate vitamin D.

as wide brimmed hats, sunglasses, a longsleeve shirt and pants.

Sunscreens are an effective way to protect yourself from too much sun exposure. However, there are several myths or frequently made mistakes concerning sunscreen. We will

I encourage my patients to spend time outdoors and enjoy all that the Brainerd lakes area has to offer. I am an avid gardener and spend hours outside in my garden. However, I also recommend diligent sun protection. Sun protection has many forms, including sunscreen, sitting in the shade, avoiding the peak hours of sunlight between 10 a.m. and 2 p.m. and sun protective clothing such review them individually.

THE HIGHER THE SPF, THE BETTER. This is incorrect. There is very little difference in the protection from the sun between a sunscreen with SPF 30 and one with SPF 100. The AAD recommends sunscreen of SPF 30 and higher. Sunscreens that have a higher SPF do not necessarily protect you better, they are just more expensive. The key for protection with sunscreen is applying enough of it. Most adults need about 1 ounce or the size of a shot glass to cover their entire body.

ARE YOU MISSING THE MESSAGE?

I ONLY NEED TO PUT IT ON ONCE. This is also incorrect. No matter what the SPF is in your sunscreen, it will only protect you for a few hours. The AAD recommends re-applying sunscreen every two hours unless you are sweating, in or near water and then it is recommended that you apply it every hour. It is important to note that water, sand, and snow reflect the sunlight, therefore increasing your risk of sunburn.

I DON’T WANT TO PUT CHEMICALS ON MY SKIN. This is a valid point and a common concern for a lot of my patients. There are two types of active ingredients in sunscreen: chemical blockers and physical blockers. Chemical blockers work by absorbing ultraviolet light and transforming it into small amounts of heat by undergoing a chemical reaction. Whereas physical blockers such as zinc oxide and titanium dioxide sit on the surface of your skin to reflect and scatter the ultraviolet light. Although these ingredients do not typically irritate the skin, they are more likely to leave a white residue or cast on the skin.

DOES SUNSCREEN HAVE AN EXPIRATION DATE?

Yes, they do. As with a lot of products, sunscreens do have an expiration date. Additionally, sunscreens are also no longer effective if they are exposed to the elements. Leaving your sunscreen in a hot vehicle, boat or camper or allowing it to freeze over the winter does result in loss of effectiveness and it should be replaced every year.

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Brainerd, MN 218-829-0946

I ONLY NEED TO PROTECT MYSELF WHEN IT IS HOT OUTSIDE AND/OR IT IS A

SUNNY DAY. This is incorrect. Despite the outdoor temperature, when the sun is up, you are being exposed to its ultraviolet radiation. Even though the sun is farther from the Earth and the intensity is less during the winter months, I still encourage my patients to use sunscreen every day. Cloud cover does not protect you from the sun. Clouds do limit the UVB wavelengths of light, but they do not stop the UVA wavelengths, so sun protection is still very important. This is the same for windows, which block UVB but not UVA light. If you sit by a window or spend time in a car, I do recommend applying sunscreen.

ALL SUNSCREENS ARE THE SAME.

This is not true. For sunscreen to effectively protect you from the sun, it should be broadspectrum, meaning that it protects you from both the UVA and UVB wavelengths of sun, it should also be waterresistant and have a minimum of SPF 30. The key to finding the right sunscreen is finding one that you will put on.

Sunscreens are now available as lotion, spray, gel, stick and lip balms. All forms of sunscreen can be effective if they are applied appropriately. Some sunscreens also come in a “tinted” form. Tinted sunscreens contain iron oxide that protects our skin from visible light. Visible light can cause hyperpigmentation or a condition called melasma. Tinted sunscreen also helps prevent the white cast that can be seen when using sunscreens with physical blockers.

We are fortunate to live in a community that has so many outdoors activities that can be enjoyed year-round. I encourage you to go outdoors and take advantage of all that the Brainerd lakes area has to offer, just make sure you are good with your sun protection, otherwise I may be seeing you in my clinic.