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Speaker 1: Welcome to brain Stuff production of I Heart Radio. Hey

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Speaker 1: brain Stuff, Lauren Vogelbaum. Here, as I record this, it

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Speaker 1: is August, which here in the Northern Hemisphere means hours

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Speaker 1: of outdoor time under the blazing summer sun. But even

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Speaker 1: though many of us do wear sunscreen to help prevent

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Speaker 1: sunburned skin cancer and the kind of skin damage that

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Speaker 1: the beauty industry calls premature aging, recent research has found

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Speaker 1: that we're not applying that sunscreen as thickly as we should,

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Speaker 1: cutting its effectiveness by about Sunscreen is rated for its

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Speaker 1: sun protection factor or SPF, with SPF thirty able to

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Speaker 1: block of ultra violet rays. The higher the SPF, the

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Speaker 1: greater the protection, although even SPF one hundred doesn't block

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Speaker 1: a hundred percent of UV light. The problem, according to

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Speaker 1: this recent research out of University College London, is that

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Speaker 1: few of us use enough sunscreen to an enjoy those

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Speaker 1: high levels of protection. Lead author Anthony Young explained to

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Speaker 1: us via email that to calculate SPF ratings in the lab,

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Speaker 1: sunscreen is applied at a thickness of two milligrams of

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Speaker 1: product for each square centimeter of skin. He said, an

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Speaker 1: average woman has about one point seven square meters or

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Speaker 1: eighteen point three square feet of skin. For a whole

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Speaker 1: body sunscreen, she will need about thirty three grams or

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Speaker 1: one point one fluid ounces. With three whole body applications

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Speaker 1: a day, that's about a hundred grams or three point

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Speaker 1: four fluid ounces. For reference, a fluid ounce is roughly

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Speaker 1: equivalent to a shot glass of sunscreen, and a large

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Speaker 1: tube of sunscreen holds just eight fluid ounces of product,

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Speaker 1: so a person spending a full day in the sun

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Speaker 1: should use about half a tube all by themselves. Are

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Speaker 1: you using that much sunscreen? Probably not. Young and his

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Speaker 1: colleagues estimate that our real life application of sunscreen is

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Speaker 1: closer to about point seven five milligrams perse. Weare centimeter

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Speaker 1: less than forty of the recommended thickness. As a result,

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Speaker 1: we're not getting anything close to the protection promised on

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Speaker 1: a bottle of SPF thirty. The good news from young

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Speaker 1: study is that you can get away with using less

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Speaker 1: product with spfs of fifty or higher. They found that

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Speaker 1: even the real world application rate of point and seven

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Speaker 1: five milligrams of sunscreen per square centimeter if using SPF fifty,

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Speaker 1: provided considerable DNA protection compared to untreated skin. So does

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Speaker 1: that mean that you should run out and buy the

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Speaker 1: most expensive SPF onere or spread your regular SPF thirty

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Speaker 1: is thick as cream cheese on a bagel. We also

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Speaker 1: spoke with Ivy Lee, a board certified dermatologist based in Pasadena, California,

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Speaker 1: who explained that you could, but that the best daily

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Speaker 1: sun protection strategy is to keep it realistic. Police said,

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Speaker 1: I tell my patients to go for the highest SPF

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Speaker 1: possible that feels good on the skin for daily use.

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Speaker 1: How do you know you're really applying two milligrams per

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Speaker 1: square centimeter? No one knows. We don't want to induce

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Speaker 1: anxiety over this. We want to build healthy habits. Skin

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Speaker 1: cancer is the most common type of cancer in the

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Speaker 1: United States, and exposure to ultra violet or UV light

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Speaker 1: is a risk factor for all types of cancer, including melanoma.

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Speaker 1: More than nine thousand, three hundred Americans die from melanoma

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Speaker 1: every year. Unprotected exposure to UV light damages the DNA

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Speaker 1: and skin cells, leaving them more susceptible to skin cancer.

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Speaker 1: DNA damage can result from either a few severe sunburns

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Speaker 1: or a lifetime of cumulative sun exposure. Incredibly, the American

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Speaker 1: Academy of Dermatology reports that getting just five or more

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Speaker 1: blistering sunburns between the ages of fifteen and twenty will

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Speaker 1: increase your overall melanoma risk. By and Lie says that

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Speaker 1: although skin cancer is less prevalent in people of color,

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Speaker 1: exposure to UV light can also cause premature aging. Daily

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Speaker 1: sunscreen use will slow the appearance of wrinkles and age

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Speaker 1: spots for all skin tones. Healthy sun protection habits include

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Speaker 1: avoiding sun exposure during the peak hours between ten am

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Speaker 1: to two pm, wearing a wide brimmed hat and sunglasses

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Speaker 1: when outside in full sun, and of course, applying sunscreen

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Speaker 1: on all exposed skin even in overcast conditions. For full coverage,

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Speaker 1: Lee recommends starting the day with a cream or lotion

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Speaker 1: type sunscreen, preferably fifteen to thirty minutes before you step outside.

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Speaker 1: Instead of measuring out a full shot glass of product,

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Speaker 1: Lee tells her clients to think of applying sunscreen like

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Speaker 1: a massage, working it fully into the skin without missing

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Speaker 1: a spot. Since body sizes vary and products spread differently,

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Speaker 1: there's no preset amount that works for everyone. Lie suggests

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Speaker 1: reserving spray or powder type sunscreens for fast reapplication on

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Speaker 1: the go. The ideal is to reapply every two hours,

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Speaker 1: but Lisa's a more realistic plan is to reapply around

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Speaker 1: lunch time if you're going to be out all day.

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Speaker 1: If you're heading out on water, sand, or snow, more

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Speaker 1: frequent applications are required because UV rays reflect off of

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Speaker 1: those surfaces. According to Lee, it's a myth that you

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Speaker 1: can't burn the palms of your hands or the soles

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Speaker 1: of your feet. Also, tablets and other handheld devices reflect

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Speaker 1: UV light to so pick a shady spot if you're

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Speaker 1: going to spend some time in the sun scrolling. Today's

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Speaker 1: episode was written by Dave Ruse and produced by Tyler Clang.

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Speaker 1: For more on this and lots of other topics, visit

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Speaker 1: how stuff works dot com. Brain Stuff is production of

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Speaker 1: iHeart Radio. For more podcasts my heart Radio, visit the

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