How Long Your Sunscreen Actually Protects You, According to Dermatologists

让皮肤科医生告诉你，防晒霜究竟能防晒多长时间

Protect your DNA!

保护你的DNA

Sun-soaking season is here, and that means if you don't lather up with sunscreen, you could be doing serious damage to your skin cells' DNA, setting yourself up to develop a potentially deadly form of cancer.

最适合阳光浴的时节已经来到，这意味着如果你不适当涂抹防晒霜的话，强烈的日光很有可能会严重损坏你皮肤细胞的DNA，最终导致你得上一种可能致命的癌症。

Melanoma kills more than 10,000 Americans every year, according to the Skin Cancer Foundation.

根据皮肤癌基金会的资料显示，在美国，每年因黑色素瘤去世的人就高达一万多名。

Those deadly cancer cases are typically caused by UV radiation you get from either baking in the sunshine, or lounging in a tanning bed.

这些致命的癌症病例通常是由于日光浴中强烈的紫外线辐射造成的，或是因为使用美黑仪器导致的。

Indulge in either of those often enough, and you may start to develop cancerous moles. If those marks aren't caught in time, the melanoma can spread to other areas of your body, and become tough to control, even deadly cancer.

经常长时间地接触日光或美黑仪器，你就有可能会开始长出带有癌变性质的痣。如果没有及时发现这些“印迹”的话，黑色素瘤就可能蔓延到你身体的其他部位，变得难以控制，甚至会引起致命的癌症。

So it's important to lather up with some protective sunscreen if you're going to be spending time in the sun - especially during warmer summer months, when the UV Index rises and the sun becomes more potent.

因此，如果要长时间暴露在阳光下——尤其是在炎热的夏季，紫外线指数升高，日光变得更强烈时——及时涂上一些防晒霜变得尤为重要。

We enlisted the help of two skin experts to explain just how long sunscreen lasts and how to re-apply it correctly. Here's their best advice:

我们邀请了两位皮肤专家来帮助我们了解防晒霜的持续时间以及如何正确地再次涂抹防晒霜。下面是他们提供的最佳建议：

Your sunscreen SPF is only 100 percent guaranteed for two hours after you put it on

当你抹上防晒霜之后，其SPF的100%效力只能保证两个小时

"When we talk about reapplying sunscreen every two hours, that number comes from how SPF is tested," John Zampella, a dermatologist at NYU Langone Health, said.

“当我们建议说每隔两个小时就要重新涂抹防晒霜时，是因为这个数字来自于SPF值的测试方式，”纽约大学朗格尼医学中心的皮肤科医生John Zampella说道。

He explained that SPF numbers are based on how much protection a certain sunscreen will give you against the sun for two hours.

他解释说，SPF值是基于某特定防晒霜在两个小时内抵御阳光的能力得出的。

When you're active and enjoying the sun, like at the beach or a ballgame, it's important to reapply after that.

当你一边运动一边享受阳光时，比如在沙滩上嬉戏或参与球类运动，最重要的是在活动结束后必须重新涂抹一次防晒霜。

If you put on an SPF of 50 at 10 a.m., by noon, "you're probably still getting some protection, but your SPF 50 is no longer accurate," Zampella said. "Maybe you're getting SPF 10 at that point."

如果你在上午10点涂上了SPF 50的防晒霜，那么到中午为止，“你可能还能获得一些保护，但此时SPF 50的防晒能力就得不到保证了。 ” Zampella 说 ，“也许你在那个时候只能获得SPF 10的防晒效果。”

For full-fledged protection, use at least SPF 30

为了获得全面保护，请至少使用SPF 30的防晒霜

That's what the American Academy of Dermatologists suggests.

这点是美国皮肤科医学会给出的建议。

SPF 30 also happens to be the dose that skin expert David Leffell, author of "Total Skin: The Definitive Guide to Whole Skin Care For Life," and chief of dermatological surgery at Yale School of Medicine, keeps on hand for himself at home.

《全面护肤：全面护肤生活的权威指南》作者，耶鲁大学医学院皮肤病外科主任David Leffell平时给自己使用的防晒霜指数也恰好是SPF 30。

For most people, that protection factor gives enough of a shield to fight off about 96% of the damaging, burn-inducing UVB solar rays outside, whether you're at the beach or on the golf course.

对于大多数人来说，无论是在海滩还是在高尔夫球场上，这种防晒成分都足以抵挡96％以上来自外部，具有破坏性且会引起灼烧感的UVB太阳射线。

Sensitive and fairer skin tones may opt for SPF 50 to get a little extra boost of protection, but Leffell says any SPF higher than 50 only offers minimal extra benefit.

敏感皮肤和偏白的肤色可能需要选择SPF 50来获得额外的保护，但Leffell说任何SPF值超过50的防晒霜能提供的额外好处十分有限。

It's especially essential to 'refresh' sunscreen in certain burn- and skin cancer-prone areas of the body and face

在身体和脸上某些易晒伤且易得皮肤癌的部位“反复涂抹”防晒霜，这一点尤其重要

That includes the top of the ears, the forehead, the cheeks, and the nose.

这些部位包括耳尖，前额，脸颊和鼻子。

Carry sunscreen with you during the day

白天的时候随身携带防晒霜

Zampella says he totes a bottle of sunscreen with him every day.

Zampella说他每天都会带着一瓶防晒霜在身上。

"Do I apply it every two hours? Probably not," he said. Realistically, he's probably applying twice a day while in the city. But he's more vigilant when he's spending the entire day outside. "At the beach, I do try and get it on every two hours."

“我每隔两个小时就抹一次吗？那不一定。”他说。实际上，在城市里，他可能每天只需要涂两次。但如果他要在外面度过整整一天时，他对此变得更加敏感。“在海滩上，我确实需要每两个小时就补涂一次。”

Make it a daily habit

让抹防晒霜成为一种日间习惯

According to Leffell, you should make putting on sunscreen everyday a part of your morning routine, "just like brushing your teeth."

根据Leffell的说法，你应该每天早上都要抹上一层防晒霜，“就像刷牙一样。”

"By making it a regular behaviour , you have a much increased chance that you won't see it as an annoyance, and that you won't forget to do it," he said.

“让这成为一种习惯，这样你便更有可能每天会记得这样做，且不会将之视为一种麻烦。”他说。

Zampella agrees. He says making sun care a daily reflex will "give you the best long term benefits of both skin cancer prevention and also anti-ageing protection."

Zampella表示赞同。他说每日做好防晒工作可以“给你提供效果最佳的长期益处，无论是预防皮肤癌还是抗衰老。”

Women should pay extra attention to their chest, while men should watch out on top of their head

女性应该更加注意自己的胸部部位，而男性则应该注意自己的头部

Leffell says women should be especially careful to protect the "v" of their chest from getting burned, since damage there is "very hard to reverse cosmetically with lasers."

Leffell说，女性应该特别小心保护胸部的“v”字部位不被晒伤，因为一旦损伤那一块位置，就“很难用激光美容修复了”。

For men, he recommends anyone who's lost a bit of hair should liberally apply sunscreen to their bald spots and their neck, and probably add a hat.

对于男性来说，他建议任何呈现脱发倾向的人都应该在他们脱发的位置和脖子上多涂抹一些防晒霜，并且有可能的话，最好戴上一顶帽子。

"We see a lot of skin cancer on the scalp," he said.

“我们见到很多皮肤癌都发生在头皮上。”他说。

Once you've lathered up, get out there and enjoy a little sun!

一旦你涂好了防晒霜，就可以大胆走到户外，享受阳光！

There's plenty of scientific research that suggests a little sunshine on a regular basis can be good for your bones, your mood, and your waistline.

有大量的科学研究表明，定期的晒太阳会对人的骨骼，心情和腰围都有益处。