by Christa Fraser

Most people know the basics of protecting themselves from the sun’s ill effects—wear sunscreen, avoid the sun between 10 AM and 3 PM, and avoid using baby oil while lying on a reflective mat. But there are a lot of sun protection myths out there. Since the rate of skin cancer in the US is now about 1 person in 35, it’s important to know the truth about sun safety.

Dr. James Beckett, a Santa Cruz dermatologist specializing in sun protection for outdoor athletes, helps us dispel these myths so we can play ‘til the sun goes down without weathering and leathering before our time.

Myth #1: I don’t need sunscreen if it’s cloudy out

Ultraviolet radiation comes in three forms: UVC, which thankfully is absorbed by the atmosphere or else life as we know it wouldn’t exist (life forms can’t survive its deadly rays); UVB, which penetrates the atmosphere on bright, sunny days—just the kind of day that makes people reach for the sunscreen; and UVA, which is constantly present, even on the cloudiest days.

UVB is the form of radiation that causes sunburn, so sunscreen might seem unnecessary for a quick bike ride or trail run on an overcast day. But while there may be less UVB penetrating the atmosphere, UVA rays can still sneak in and age you prematurely.

Myth #2: A base tan is a good idea at the beginning of summer

According to Dr. Beckett, “Any type of sunburn represents massive damage to cells.” Sunlight actually hits the human body right where it hurts most—in the nucleus of cells, with a sucker punch to the cell’s DNA. Over the long haul, the DNA in skin cells starts to make mutations and these mutations add up over the years—those new freckles on your shoulders may actually be the result of that thru-hike of the John Muir trail you did ten years ago.

In fact, as Dr. Beckett explains it, up to 80% of a person’s sun damage has already been incurred by the age of 20. Add to that another decade or four of whitewater boating, mountain biking and al fresco beers and the potential for skin cancer and premature ageing seems obvious.

Myth #3: UV rays can’t go through glass/my hat/my sunglasses, etc.

You can run but you can’t hide—UV rays will find you. UVA rays penetrate glass quite easily, even through car windows. Most people are aware that wearing glasses can protect against cataracts, but few realize that melanomas from sun exposure can appear on the eyes, as well as the skin. For this reason, only buy sunglasses that list their UV protection on the label.

Even clothes can’t filter out UV rays completely. Fortunately, tightly woven clothes can offer up to SPF 50. Some brands actually list their SPF on the label. Wear at least an SPF 30 long sleeved shirt, long shorts and a broad-brimmed, tightly woven hat while outside and you can deflect the worst of UV rays.

Myth #4: Sunscreen is sunscreen. It’s all the same.

Sunscreens can be evaluated three different ways: by the amount of Sun Protection Factor (SPF) they offer, whether they protect against UVA, UVB or both types of rays, and by their ingredients.

SPF is the measure of how much radiation is blocked by the lotion. A common misconception is that anything over SPF 15 is redundant and that SPF 15 offers sufficient protection on an overcast day. However, as Dr. Beckett explains, “SPF 30 sunscreens have been shown to result in significantly reduced levels of microscopic injury to epidermal cells than SPF 15 sunscreens given comparable ultraviolet radiation exposure.” These microscopic injuries to the skin set off an immune system red alert deep in the body. SPF 30 blocks some of the cellular damage that SPF 15 can’t stop.

In Addition to listing SPF, a sunscreen label should say either broad spectrum, UVA/UVB or full spectrum. Otherwise, it probably only protects against UVB rays.

In the old days, a solid stripe of white zinc oxide coating the nose, lips and undereye areas was the ultimate in sunscreen. Not much has changed. “The most effective forms are still zinc oxide and titanium dioxide,” explains Dr. Beckett. Fortunately, the newest forms of these ingredients are micronized and slather on to an invisible sheen. White zinc stripes today are just for retro beach cool.

Myth #5: If it says waterproof and sweatproof, it will last all day.

For athletes, a sunscreen that advertises water and sweat resistance is a good investment. However, every time you swipe the sweat from your forehead, towel off from that last wave or scratch the poison oak patch on your calf, you’re stripping the sunscreen from your skin. And sunscreen does get diluted from sweat and water. A good rule of thumb is to always reapply your sunscreen every two to three hours, especially if you’re working up a good sweat.

Should Iavoid the sun at all costs?

Global warming has now moved from the realm of conspiracy-theory and urban legend into declared fact. We are cooking the planet and ourselves like never before. The ozone hole is swirling above the poles and growing bigger—so big in fact, that Australia has developed a skin cancer ratio of one person in 15. Like Californians, Australians love sun, surf and sky. To combat the effects of the sun, they have developed a campaign to keep people safe outside. “Slip, slap, slop”—slip on a shirt, slap on a hat and slop on the sunscreen. Follow their example and enjoy the sun safely.