Applying sunscreen

Instructions for applying sunscreen seems, well, unnecessary... afterall what does one need to know beyond: squirt into hands and apply all over exposed flesh? Well, the thing is, I've observed people apply too little with their expired SPF-12 lotion with no UV-A protection whatsoever (you know who you are). Why not just sprinkle yourself with chicken blood (or, if you are vegan, soy sauce) hoodoo? It's just as effective.

Sun damage is cumulative, so it's best to minimize it. Here are three simple tips:

• What to apply: Get broad-spectrum "sweatproof" sunscreen that protects you from both UV-A and UV-B rays. Not all sunscreens are created equal. In fact, the Environmental Working Group claims in its study that 4 out of 5 (84%) are ineffective or unsafe. For UV-A protection (against aging), look for zinc oxide, titanium oxide, avobenzone, or ecamsule in the ingredients. For UV-B protection (against burning), look for at least SPF 30.
  Costco sells Neutragena sunblock*—which claims to meet all criteria, plus it's non-comedogenic (won't block pores) and feels light on the skin—for a good price. If you'd rather use something else, you can check out a database of tested suncreen. And do keep an eye out on the expiration date.
• When to apply: Apply 30 minutes before sun exposure, and reapply every few hours. Be OCD if you are fair-skinned.
• How much to apply: You need an ounce of sunblock to cover your entire body (more if you are a big guy). An ounce is about 1/3 of a standard-sized Neutrogena tube. You need to apply half a teaspoon each for the face, neck, and arms; and a full teaspoon each for the chest, stomach, back, and legs. Don't forget your ears and the top of your shoulders!

For some background on UV-A and UV-B, see the previous post. Physical protection, such as wide-brimmed hats work great, too, but don't forget about reflected radiation. Bah, just get a burqa. Maybe one made from reflective tin foil.

* Neutrogena also contains oxybenzone, which a few animal and lab studies suggest might release free radicals and mildly affect hormone systems, however these studies did not show harm in sunscreen users. In any case, the risk of not applying sunscreen is many multiples worse (as assessed by the American Cancer Society)!

If you're really creeped out by chemicals, you can use suncreen that contains inorganic particulates, such as zinc oxide and titanium dioxide.

Sun damage while driving

You still can get sun damage inside some cars. True, it's unlikley that you'll get a sunburn while driving, not even in long road trips, but incremental damage does happen and accummulates over the years.

In most cars, the windshield is treated to filter out UV-A radiation, which accounts for wrinkling, but the side and the rear windows only partially filter out UV-B radiation, which darkens skin. So while you might not darken, you still get wrinkly and all. Boo! (But a few car models actually have better UV-A and UV-B protection).

You can have the windows professionally treated to block out UV rays without tinting or affecting visibility. Incidentally, in California, all new automoblies are required by law to have heat-blocking (either by deflection or absorption) glass by 2012. This makes environmental sense since one will need less energy to cool the car.

p.s. If you can never keep track of which one is UV-A and which one is UV-B, try this menmonic: UV-A causes skin Aging; UV-B causes skin Burning. Both types contribute to cancer.