Sunscreen provides a screen , not a block. In the same way, the sun lotion or potion of your choice allows some small amount of UV radiation onto your skin.
SPF stands for sun protection factor. The higher the number, the less UV passes through. An SPF of 30 allows one-thirtieth or 3. This means it filters Put another way, if your unprotected skin would take ten minutes to show signs of burning, then properly applying SPF 30 sunscreen would slow the rate of burning to the point where it would take 30 times longer, or minutes in total. But this is perfect world stuff. If you extend your stay in the sun for minutes over eight hours!
Read more: Explainer: what happens to your skin when you get sunburnt? At a microscopic level, the skin is a series of peaks and troughs. Layering on sunscreen around 20 minutes before going into the sun allows the product to flow into the troughs and bind properly to the skin. Many sunscreens recommend reapplying every two hours. But another way to look at it is like painting a wall of your house.
And this will cover the bits you may have missed, or covered too thinly, on first pass. Also, use it generously. Most people use too little between a quarter and three-quarters of the amount of sunscreen necessary to achieve the sun protection claimed on the label.
A teaspoon per limb is a good rule of thumb. Putting on more sunscreen every two hours helps keep you protected. It's important to remember to re-apply after swimming or water sports also. Many people mistakenly believe they only need sun protection on hot, sunny days.
However, it is Ultraviolet UV radiation from the sun, not heat, that is the major cause of sunburn, premature ageing, eye damage and skin damage leading to skin cancer. UV can't be seen or felt. Because of this, it can be damaging without us knowing it at the time. The UV index tells us the strength of UV radiation each day. Sun protection is recommended when the UV index is three or higher. Often, the UV can be high on cool, cloudy days. A great way to keep track of the UV index where you are is via our free SunSmart app which can be downloaded here or by checking our myUV website.
Read more about how to be SunSmart on our myUV website. Found in: News - View all news. Setting new priorities after cancer treatment. Have you or someone you love recently completed cancer treatment? Are you Sunscreen is just one vital part of a strategy that should also include seeking shade and covering up with clothing, including wide-brimmed hats and UV-blocking sunglasses. Steven Q. Wang is a board-certified dermatologist with fellowship training in melanoma, Mohs surgery, dermatologic surgery and laser surgery.
He is actively involved in clinical research, with a focus on photoprotection and the development of noninvasive imaging technologies to diagnose skin cancer. How high should I go? UVA rays cause skin damage that leads to tanning as well as skin aging and wrinkles.
The shortest wavelengths of UVA rays also contribute to sunburn. Updated June 9, About the expert: Steven Q.
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