• Question: How often should you apply sunscreen to ensure protection from UV rays?

    Asked by GregP_WN on Friday, November 9, 2012

    Question: How often should you apply sunscreen to ensure protection from UV rays?


    11 Answers from the Community

    11 answers
    • nancyjac's Avatar

      hmmmmmmmm.....somehow I get the feeling this might be a rhetorical question :-)

      The two primary factors that determine this are the sun protection factor (SPF) of the sunscreen and activity which can remove the sunscreen or degrade the SPF. The rule of thumb for SPF is that the SPF rating is the multiplyer of how long you can be in the sun without burning as compared to no sunscreen. That of course varies by individual skin type. Those with fair skin may burn with only a few minutes exposure while others may be able to tolerate considerably more. For example, for someone whose skin begins to burn after 20 minutes of exposure without sunscreen, a sunscreen with an SPF of 15 should be applied every 5 hours (15X20/60).

      However, regardless of the SPF number, sweating, swimming, showering, etc. remove sunscreen and/or cause the SPF value to degrade. Even sunscreens that are water resistant or waterproof begin to degrade in water after 40 or 80 minutes respectively.

      almost 4 years ago
    • ticklingcancer's Avatar

      This is definitely an area where I should pay close attention. I've had so many sun burns on my head...What's sad is that I know I should use sunscreen but I don't. I've gotten to where I wear bandanas on my head but don't really think about the rest of my body.

      almost 4 years ago
    • Queen_Tatiana's Avatar

      Apply every 90 minutes as the sweat weakens it's protection. If you go in the water apply you should reapply as soon as you dry off--even if using waterproof, as the water will weaken the lotion strength to protect.

      It has taken me along time to even realize I must use sunscreen--I gew up on the beaches of S. Calif, and you wouldn't believe what we used to tan with and firmly believed that darker was better. That is the past and now I do use sunscreen.

      almost 4 years ago
    • leepenn's Avatar

      The bottle usually has instructions... and there are a few issues...

      Here is my favorite resource on sunscreen safety.

      With recommendations in regards to the best sunscreens....

      TC - honestly, a bandana on your head is probably better than sunscreen!

      I race bikes, and so I get a lot of sun. I wear these things called arm coolers on my arms during the height of the summer. The idea is that they protect from the sun and wick sweat away from my skin to the exterior of the cooler, which allows for evaporation and thus cooling. I often wet them using my water bottle for added cooling. Surprisingly, they work pretty well. I ALWAYS wear UV protective eyewear...

      Anyway, there are some ingredients to avoid - one is oxybenzone, which has been implicated as an endocrine disruptor... as well as the molecules it breaks down into over time...

      So... I hope that helps! This time of year, we don't get much UV up here in the North... so sun burns are pretty darn rare and vitamin D levels are dropping...

      But come March / April, I've always got to remember to start protecting my skin again....

      Hope you have a good weekend,

      almost 4 years ago
    • carm's Avatar

      Greg, you know, of the many questions posed here at "WhatNext," this question is the one that always presents a conundrum for me. When I worked in research, I did a study with a pharmaceutical house called Galderma that was testing a lotion for people who were sensitive to sunlight. During that study, I did some side research and spoke with some biochemists from Eastern Europe who seemed to have a different perspective on the harm sunlight can do. They feel that the sun produces Vitamin D in the skin as a byproduct of cholesterol. This in turn removes the excess cholesterol in the skin. Today we know that Vitamin D helps to reduce the incident of many carcinoma's including skin cancer. Yet it seems that geographically, the closer you live to the sun, the higher incidence for skin cancers. These chemists think it is because of the sunscreen that is used. They explained that some sunscreen ingredients contain photoreactive agents that become a carcinogenic when exposed to acute sunlight. They also felt that they contain persistent cancer causing agents like zinc oxide, titanium dioxide, and/or aluminum hydroxide when used chronically over long periods of time. Skin cancer really never became an issue until the production of sunscreens took off, yet so many people suffer from Vitamin D deficiency because of lack of sun. Therein lies the conundrum. I grew up at a time when baby oil mixed with some tincture of iodine was the best way to seek a tan and prevent a burn. Never had a problem or knew of anyone who did. I understand that the UV rays can be harmful, but so too is the prevention. It seems that as time moves forward, diseases emerge more frequently with the advent of either the method of detection, or the prevention. Breast cancer was really not all that significant until the advent of the mammogram. It is now estimated (NCI estimates) that a mammogram is equal to 3 chest xrays in the amount of radiation, an abdominal CT equates to 25 chest xrays. Heck, a CT of the abdomen radiation dose when compared to natural radiation from the sun is equivalent to 3 years in the sun, a mammogram is 3 months. I have been told that many people across the pond rely on holistic sunscreens and maybe that is the way to go. Im sure I did not answer your question, but I hope I gave you pause for thought, Carm.

      almost 4 years ago
    • geekling's Avatar

      I don't use sunscreen at all. I am relatively dark skinned and I enjoy the feel of the sun on my body.
      When I get too 'warmed' I simply go into the shade. I also have a simply lovely sun hat and am capable of putting on clothes or going to the shade. I like the mornings and late afternoons and try to avoid being out in the noon time sunlight. I am neither, as the saying goes, a mad dog nor an Englishman. I also find that sunshine is something one works up to in that, for example, one must slowly increase tolerance for exposure after a prolonged time without sun directly on the

      I remember the oncologist I chose remarking "Well, you certainly did not get that cancer from smoking or sunlight."

      I hold the Environmental Working Group in high esteem.

      almost 4 years ago
    • Carol-Charlie's Avatar

      This was simple for me. The person who preferred a tan, but we've all learned. My oncologist simply said. STAY OUT OF THE SUN. I did as I was told. My son commented a few years ago...Mom... I have never seen you so white!!!!! I have no pigment on a large part of my right arm, and it always embarrassed me in school, I was so white... you couldn't see the 'whte' mark. Now... I usea self tanning cream. my skin has never looked so good, and I don't have to put on make up. I'm pretty sure you've never had the 'makeup' problem. But it was rater easy for me to sit in the shade 'wear my wig' (or hat) - long sleeve shirts outside.

      almost 4 years ago
    • GregA0406's Avatar

      Like most answers, each needs to be adjusted to the individual. In my case, I am currently in Clinical Trials and one side effect of the drug is sun sensitivity. I enjoy golfing and the lake. So, the dermatologist I see at MSKCC recommended every 2 hours with an SPF of at least 60. He also suggests unscented. Personally, I have used Neutrogena UltraSheer SPF 70 for over 3 months. I also wear a wide brim hat whenever possible. I have had no skin issues.

      almost 4 years ago
    • SueRae1's Avatar

      Every morning and then it depends on how much i am outdoors. I reapply about every 2 hours.

      almost 4 years ago
    • tomget's Avatar

      I've read and heard so many conflicting things about sunscreens that in my case..peoples situations vary.. I don't use any sunscreen and just follow the "cover up method". Meaning i mostly wear a hat with a brim..straw hat etc..works for where I live..and long sleeve shirts..and remember not to hang my arm out the car window and things like that. But like I said it varies for peeps lifestyle and specific medical situation. Plus i get checked out by a dermatologist every year or so, because I've had some milder forms of skin cancer frozen or surgically removed over the years.

      almost 4 years ago
    • HalfFull's Avatar

      Have you looked at the sunscreen clothing at www.coolibar.com? My husband bought a pair of driving gloves to protect his hands when he drove his mini cooper convertible this summer. They have a wide variety of clothing from children to adult; our daughter made us aware of sun screening clothing when she bought them for the grandchildren.

      almost 4 years ago

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