Sunscreens - Frequently Asked Questions
What is SPF and does it matter?
SPF is short for sun protection factor, and is a measurement of how long it takes to cause redness due to sun exposure. It is a ratio measured under laboratory conditions which compares the length of time it takes to get sunburnt without sunscreen, against how long it takes to get burnt with sunscreen on.
SPF does matter, particularly if you have light colored skin, which burns easily. Those with lighter skin should use a sunscreen with a minimum of SPF 15, preferably 30 or higher. Above that point, however, there is almost no difference in quality of protection because the sunscreen blocks most of the UVB rays anyways. Far more important are how much sunscreen is used, and how often it is reapplied.
How much sunscreen should be applied?
The short answer is, much more than you think. Polls from research have repeatedly shown that people use far less sunscreen than required for effective use, so that the sunscreen protects the skin as advertised. A good measurement should be a shotglass full of sunscreen for the body and the face.
What are some things to look for in a sunscreen?
- Broad spectrum protection (protects from both UVA and UVB)
- SPF 15 or higher
- Produced from a reputable company
- Consistency of the sunscreen and personal preference
Can sunscreens prevent cancer?
There is a lot of evidence that sunscreens reduce the chance of developing skin cancer, and pre-cancerous legions called actinic keratosis, which can later turn into a skin cancer. Additionally, sun damage also causes other skin problems such as wrinkling, and premature aging, which sunscreens can help prevent.
Do I need to reapply sunscreen?
Yes, reapplication is important. All sunscreens degrade when exposed to sunlight. Ideally, sunscreens should be reapplied every hour to ensure that it is fully protecting your skin. Water, sweat, and wind are all real life factors that can weaken sunscreens. Remember that SPF is measured under laboratory condition, which don't account for any of these common factors on the beach, or in the mountains.
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