Burn Baby Burn

So far this spring I have managed to get myself stung by a bloom of poisonous jellies in Florida, suffered an epic altitude-enhanced hangover in Lake Tahoe, and can now add to my 2011 miseries a wicked sunburn suffered in Cape Cod. Now I am normally so careful about applying sunscreen at regular intervals, that I am a bit embarrassed that I let this happen, and in quite a bit of pain to boot. You see, I bought this new sunscreen with an SPF rating of 100. It was the same price as the SPF-50 I typically wear, and figuring it lasts twice as long, I'd be getting twice the protection for my money. Judging by the fact that I look (and feel) like I was rolled around in a frying pan, I have decided to take some time indoors and bone up on my sunscreen facts.

So I assume you know that SPF stands for Sun Protection Factor, but do you know what that really means? Do you think that SPF 100 enables you to spend 100 minutes out in the sun, or that it blocks twice as much sun as SPF 50 (like I did)? Well, you'd be wrong on both accounts, and find yourself sitting in your timeshare rental burnt to a crisp, just like me. So here's the deal: there are three types of Ultra Violet (UV) rays - A, B and C. The ozone layer, when it doesn't have a big hole in it, keeps almost all of the UVC away from us. UVA is what you seen under the lights at a disco, or if you are not as old as I am, a rave. UVA travels through windows and penetrates deep into your skin, and are the rays typically associated with premature aging of the skin. You ever see those old folks at the beach who never seem to burn, but instead look like large, greasy raisins? That's UVA's handiwork, and those folks may not be as old as you think. UVC, on the other hand, cannot travel through barriers like glass, and are most responsible for sunburns, and certain cancers of the skin. SPF refers the the blocking or reflecting of the UVA and UVB rays.

So what are the SPF numbers all about? As a starting point, there is a set time limit each of us can spend in the sun before our skin begins to burn. For me, this is about 10-20 minutes. Everyone's base number is different, and like IQ or net worth, just about all of us overestimate this figure. So SPF is the factor by which you can extend your time in the sun. So my usual SPF-50 extends my time before burning from 10-20 minutes to 500-1000 minutes. And therefore, SPF-100 takes me up to 1000 - 2000 minutes. There's only 1440 minutes in a day - so how the heck did I get a sunburn?

The fact of the matter is that almost no one applies enough sunscreen. Do you know how much sunscreen it takes to cover your body in order to satisfy the SPF number? Try 1 oz. That's a shot glass folks, each time you apply. Another way to think of it is that the 3oz tube that has become so popular since carry-on liquid restrictions went into place is enough to last just three applications. Now this may seem like a tremendous amount of sunscreen to you, and you might suspect that I am getting some sort of kickback from the sunscreen industry, but the fact is that the SPF number is based on a 1 oz application. If you are like me, and I hope you're not, you put your sunscreen on very thinly, and that 3 oz tube will last you all summer and beyond. All I can say is that sooner or later, you are going to end up looking like a strip of bacon.

So aside from the fact that I getting about 1/10th the protection I think I am by not applying enough, sunscreen degrades as you wear it. Quickly. Swimming, sweating, and sunlight break down sunscreen in about 2-3 hours - even the waterproof stuff. And as anyone who has ever been to the beach knows, swimming, sweating, and sunlight are pretty much what it is all about. So regardless of your SPF number, you are pretty much out there naked (figuratively, let's hope) after 2-3 hours.

So my advice to you is to apply a high SPF sunscreen liberally and often, and don't overestimate how much time it takes to burn your skin. Feel free to continue to lie about your IQ and net worth, however. No one believes you anyway.