Today is the opening of the outdoor pool in the city where I am spending sabbatical in Israel, and in honor of that, let’s talk about the science of swimming and swimming pools.
1. CAN I PERMANENTLY DAMAGE MY EYES FROM SWIMMING WITHOUT GOGGLES AND WITH MY EYES OPEN? This happens to me all the time because my kids are always stealing my goggles, and then demanding that I go underwater to locate all kinds of non-buoyant toys. Luckily it turns out I am not permanently damaging my eyes! Hurray! The pH of pool water is usually mildly basic (between pH 7.2 and 7.8). What happens if the pH is higher? Too basic solutions will irritate your eyes, as will solutions below 7.2 (because the lower pH causes the chlorine to be in a form that has greater access to your eyes). Don’t make a habit of swimming with your eyes open underwater, but usually you will be OK.
2. WHY DOES MY HAIR TURN GREEN FROM TOO MUCH SWIMMING? I mean, my hair usually doesn’t, because it is dark and covered, but a lot of people do have green-tinged ends from lots of swimming pool time. What causes this? Metals in the water are oxidized by chlorine, which causes a color change to green in many of the metals. Spend lots of time in the water, and the metals will stick to your hair and make it green. This greenish tinge is particularly prevalent for people with light colored hair, probably because it is easier to see.
3. DOES SPENDING TIME IN THE WATER WASH OFF YOUR SUNSCREEN? No, not unless you put it on and jump right in immediately after. If you do that kind of sequence, the sunscreen will wash right off and you will be completely unprotected. So wait at least a few minutes (exact amount of time depends on the sunscreen brand) before getting wet. After that, enough of the sunscreen should be absorbed into your skin to make sure that it won’t wash off, at least not right away.
4. WHY DO I HAVE TO WAIT AFTER I EAT TO GO SWIMMING? Short answer is, you don’t! This was a myth for a long time that you would end up with bad cramps and drowning, or that digestion diverted necessary blood flow from your limbs, resulting in easier fatiguing, cramping, and drowning, or a variety of other reasons why swimming after eating is ill-advised. True answer? It really really really doesn’t matter and you don’t actually have to wait between eating and swimming at all!
Sometimes I even like to eat and swim at the same time! (Not really, but that could be fun.) Happy swimming, readers!