Swim Bits – May 2021 – Oregon Masters Swimming

Last month a coterie of Corvallis Masters swimmers came to Eel Lake to camp out in yurts and tents at Tugman Park and to swim in the lake. Since the water temperature at the time was 49.5, F., I admired their courage. Proof of their doughty immersion are in the accompanying photos.

Their accomplishment reminded me that it is time again for the yearly caution of swimming outdoors without sunblock protection. Many swimmers don’t use any sunblock when swimming outdoors. I’d like to persuade them to do so by starting with an interesting graph. Go to the attached photo or to https://en.wikipedia.org/wiki/Ultraviolet_index#/media/File:UV_Index_NYC.png

The graph is for New York City, but in general it will do for us. NYC is 40.7146 latitude; Salem is almost exactly between the equator and the North Pole. According to the graph the safest times to swim in full sun are before 9 AM and after 3 PM. The UV Index triples between 8 AM and Noon. The old bromide is appropriate here with a slight modification: “Mad dogs and Englishmen [swim] in the noon day sun.”

However, for many Masters swimmers noon may be the only time available due to family and/or work schedules. Then what sunblock should a swimmer use outdoors between sunrise and sunset? The simplest answer is “none without Zinc Oxide and/or Titanium Dioxide.”

According to every dermatologist I’ve ever talked to and most articles online, the only sunblocks that actually “block” most UV rays are Zinc Oxide (ZnO) and Titanium Dioxide (TiO₂). Yes, they put a coating on your skin, but I’ve found that a small price to pay every time I get in a pool because they can lessen more pre-cancerous actinic keratosis cells on my face.

Other chemicals only affect UV rays after they penetrate the skin. Such chemicals do not “block” UV. Why use a chemical that allows UV rays into your skin before doing something about the UV? In addition oxybenzone and octinoxate are banned in Hawaii because they kill coral. You want coral killers on your skin?

So read the labels on any lotion that says it is a sunblock. Many are not blockers. They do not use ZnO and/or TiO₂. Any true sunblock will have either ZnO or TiO₂ or both in them. Look for higher percentages of ZnO and TiO₂, 4+% or more. I also have had great success using sunblocks made especially for kids, but again only trust the actual list of ingredients for ZnO and TiO₂.