By David Freidson | Posted: Tuesday, May 27, 2014 12:00 am
Dateline-Saturday, May 17, 2014. City-Plymouth.
The first nice weekend day of the spring. I saw kids across the street setting up a lemonade stand; a couple walked by with their dog; a family biked by our house; people were tending to their yards-a buzz was in the air.
This was the first day of spring that the Freidson family was going to walk to the park.
The temperature was in the upper 60s. My wife and I didn't want our kids to be too cold so we made sure they wore pants and long-sleeve shirts.
After the 15-minute walk to the park, 30 minutes spent at the park and the 15-minute walk back, we were home. I noticed my kid's cheeks were pink. I figured it was just the playing they did that caused the pinkness and that it would go away after a bit inside. After a couple of hours the color persisted.
Uh oh, the kids were a bit sunburned. My 20-month-old son actually had a slight fever due to the sun.
The guilt set in. How could I let my kids get sunburned? Why didn't we put sunscreen lotion on them? We were so focused on keeping our kids warm enough we didn't think about protecting their skin from the sun. The only good thing out of this experience was that I came up with the topic for my monthly column -how hot does it have to be to get sunburned?
The answer I discovered in my research is that it depends. It isn't the number on the thermometer that counts; it is the ultraviolet (UV) index number that counts.
The sun basically emits energy over three wavelengths: Infrared radiation that we feel as heat, visible light that you can see and UV radiation that you can't see or feel. UV radiation is what affects the body.
UV radiation helps the body produce vitamin D, which is great. But what isn't so great about UV radiation is that it causes skin cancer, premature aging of the skin and cataracts.
The UV index is a one to 11 scale created by the United States Environmental Protection Agency.
Before my research, I had falsely thought that the EPA mainly only monitored businesses to ensure they weren't producing harmful chemicals for the environment. But I discovered the mission of the EPA is "to protect human health and the environment." Too much UV radiation is harmful to human health so I can see how it fits under the EPA's jurisdiction to monitor these waves.
The higher the number on the UV index, the higher the amount of UV radiation that reaches the earth. Two or less is low; three to five is moderate; six to seven is high; eight to 10 very high; and 11+ is extremely high.
These numbers don't mean anything by themselves. But there is a great chart used to determine time for unprotected skin to burn based on the UV index number. Two and below, it takes 60 minutes to get burned. Three to four is 45 minutes; five to six is 30 minutes; seven to nine is 15-25 minutes; and a UV index number of 10 or higher burns skin in 10 minutes.
The UV index numbers are also a guide on the type of sun screen that is recommended. Generally below three, no protection is needed.
SPF 15 sunscreen is recommended when the UV index number between three-7.9. SPF 30 is recommended for a UV index of 8-11.
"That's nice," you say, but how do you know what the UV index number is so you can protect yourself and your family properly?
Every day the National Weather Service posts the high UV index number for each major city. To search by zip code, you can go to, www2.epa.gov/sunwise/uv-index.
For the 58 percent of Americans that have a smart phone, there's an app for that. I downloaded the free UV index app from the EPA-it's great. You can see what the UV index is by hour.
Common sense would say that the cloudier it is, the lower the UV index is but that isn't always the case. And temperature is not the best indicator of the UV index. We know it can be 80s at night and obviously there is really no UV rays getting to earth at night.
My suggestion is to get the app on your phone if you can. And when in doubt, you can't go wrong with too much protection: Hat, sunglasses, UV protection clothing and 30+ sunscreen.
David Freidson is a licensed chiropractor and works out of the Synergy Health & Rehabilitation office in Minnetonka. To learn more, visit www.synergyhealthmn.com or call 952-475-4080.