I was in outdoor Mingus Park Pool on the Oregon coast at noon one day this spring, and I was asked, “What SPF should I use?” I’d put on my standard sunblock in the locker room that day so I guess that made me some sort of expert on sunblocks. I just answered with what my dermatologist has said to me many times.
Use physical sunblocks such as Titanium Dioxide (TiO2) or Zinc Oxide (ZnO). Don’t depend on chemicals to block the sun even if they say they are SPF 30 or higher. Such chemicals have to be absorbed into the skin to work. That’s not blocking the sun’s UV rays from reaching your skin as TiO2 and ZnO do. One chemical commonly used in sunscreens, oxybenzone, kills coral even in very small amounts. Save the coral and your skin. Avoid it.
Unfortunately, I and many like me grew up with the idea that getting a suntan was a good idea. Even now, because I swim outdoors all year, usually in lane one where the shadow from the pool building covers the water, I still have tan lines. I also have pre-cancerous actinic keratoses on my head and arms that develop regularly.
I see my dermatologist every six months, and she removes the keratoses by freezing it with liquid nitrogen. It stings a bit and blisters develop, but I am careful to keep the lesions clean and dabbed with Neosporin until they heal. No big deal.
Skin cancer, though, is a big deal. Protect yourself. Use no skin block under SPF 50. Read the list of ingredients. If the list is only chemicals, don’t buy it. Look at the products for babies and kids. They usually have TiO2 and/or ZnO. I’ve seen one with 21% ZnO. Wow!
Next, use the sunblock every time you swim outdoors. I know that some people don’t like the white smear that you can get from ZnO and TiO2. There is clear zinc oxide on the market with two chemicals in it (not oxybenzone). Find that and use it.
Last, you might consider not swimming at noon in the sun. I stop swimming at noon when the shadow disappears as the sun gets higher. If you don’t have a choice, put sunblock on your face, arms and back, wear a cap covering your ears, and don’t stay more than an hour. Only mad dogs and Masters swimmers go out in the noon-day sun.