Крем с SPF?

Надо же, я угадала :-) (горжусь собой :-)

[Masha]

В любом климате нелишне защищать лицо дневным кремом с фактором не меньше 15. Ну, если не полярная ночь, конечно . Так что "не заморачиваться и домазать".

Dear Paula,
Thank you so much for revolutionizing my skin-care routine! Even though I have much faith in your research and your dedication to consumers, I keep getting hung up on the issue of sunscreens and how to use them. I keep reading that reapplying sunscreen is essential, usually every 2 hours. If a sunscreen with SPF 15 is designed to let me be out in the sun all day, why should I have to reapply? Do sunscreens lose their effectiveness on the skin after 2 hours (for example, if I apply at 8 a.m. but am not exposed to the sun until 4 p.m., will it still provide protection?), or is it depleted after 2 hours in the sun? Reapplying so often makes my skin feel too slick and laden with product, not to mention it disturbs my makeup.

Jesse, via email

Dear Jesse,
If you are spending long periods of time in the sun, especially under extreme sun exposure conditions, there is research showing that frequent application of sunscreen, every two hours as you mentioned, does have validity. According to information on the American Academy of Dermatology's Web site (www.aad.org), "a study followed 105 skiers in Vail, Colorado over a one-week period in January. Each participant was given an unmarked bottle of sunscreen (either SPF 15 or 30) and instructed to maintain a log of the amount of time they spent outdoors as well as the amount of sunscreen applied.... The study concluded sunscreen, when used correctly, was an effective defense from sunburn when in an open aired, highly elevated, sun exposed and sun reflective environment." However, those who applied the sunscreen after 2.5 hours or longer "were five times more likely to sunburn compared to those who applied sunscreen every two hours or more."

What is important to keep in mind about this information is that this study was done on skiers who were exposed to about 40% additional UV intensity than most people due to the reflection of sunlight off the snow. Also, "[UV] intensities at altitudes of 8,000 to 11,000 feet have been shown to be 60% to 80% higher than at sea level."

If you are not experiencing sun exposure under those conditions, you can follow the standard time guideline for an SPF rating, which is the SPF number multiplied by the amount of time you can usually be in the sun without burning (turning pink). For those with lighter skin tones, the formulas look like this-SPF 15 X 15 minutes = 225 minutes (or 3.75 hours) of protection or this-SPF 15 X 10 minutes = 150 minutes (2.5 hours) of protection. Whether or not that means continuous time in direct sun exposure or simply time of wear from the moment you apply sunscreen isn't clear. Having spoken to a number of dermatologists they each seem to have different opinions (even some who just said to "wear an SPF 50 and you'll be fine," which is bad advice because it doesn't address the issue of liberal application, UVA protection, and sun behavior). Even the FDA has varying explanations on its Web site.

Bottom line, it is without question safer to frequently apply a well-formulated sunscreen if you are planning to spend long periods of time exposed to the sun, especially if you aren't able to comply with other sun-smart behavior, such as avoiding deliberate tanning with indoor or outdoor light; seeking shade; wearing protective clothing; limiting exposure during peak hours; and covering up with hats, sunglasses, and UV-protective clothing whenever possible.