It helps plants grow, keeps us warm, and who doesn't love to lie on the beach on a sunny day?

太陽によって植物が育ち

But for all of it's good qualities, the Sun can also be harmful in large amounts.

私たちは温まります。

That's why we invented sunscreen.

晴れた日にビーチで横になるのが嫌な人なんていないでしょう？

The purpose of sunscreen is to shield the body from the Sun's ultraviolet rays, which have several harmful effects, including sunburn, aging, and skin cancer promotion.

良い面もある一方で

These rays are separated by their different wave lengths, into types such as UVA and UVB, which exert a variety of effects in the skin due to the absorption patterns of chromophores, the parts of the molecules responsible for their color.

太陽には有害となりうる点も多くあります。

The primary two chromophores are hemoglobin, found in our red blood cells, and melanin, which gives our skin its pigment .

だから日焼け止めができたのです。

We know that UVB rays cause the skin to burn.

日焼け止めの目的は、体を

The role of UVA rays is less well understood and appears to have an effect on our tanning response, carcinogenesis, and aging.

太陽からの紫外線から守ることです。

So, how does the sunscreen protect us from these rays?

紫外線にはいくつか弊害があり

There are two basic types of sunscreen, physical and chemical blockers.

例えば日焼け、

Physical blockers, like zinc oxide or titanium dioxide, reflect the Sun's rays by acting as a physical barrier.

老化、

If you've seen lifeguards with noses covered in white, then you know what this looks like.

皮膚がんの助長などです。

The same ingredients are primary components of diaper creams, where the goal is also to create a physical barrier.

これらの光線は

Historically, they haven't always been easy to apply and were conspicuously visible on the skin, but new formulations have made this less of an issue .

波長の違いで

Chemical blockers, on the other hand, absorb the Sun's rays.

紫外線A波や

They deteriorate more quickly than physical sunscreens because their ability to absorb the Sun diminishes.

紫外線B波に区分され、

Generally, these are more transparent when rubbed on the skin, but some people develop allergic reactions to some of the chemicals.

皮膚に様々な影響を及ぼします。

Regardless of the type of sunscreen, all are subjected to testing to determine their sunburn protection factor, or SPF.

その原因は、発色団の吸収パターンによるものです。

This is essentially a measure of the protectionthat the sunscreen will provide from UVB rays before one begins to burn.

発色団とは分子の

But even if you don't burn, you still need to use sunscreen because unless you live in a cave, you're not immune to the effects of the Sun.

色に関連する部分のことです。

It is true that darker skinned people and those who tan easily have more built-in protection from sunburns, but they are still vulnerable to the effects of UVA.

主要な発色団は2種類あって、ヘモグロビンは

Children under the age of six months, on the other hand, should have almost no sun exposure as their protective mechanisms are not fully functioning, and their skin is more likely to absorb any sunscreen that is applied.

血液細胞中に存在し、

Wearing sunscreen helps protect against the development of all three types of skin cancer: basal cell carcinoma, squamous cell carcinoma, and melanoma.

メラニンは肌に色素を与えるものです。

On a daily basis, the DNA in your cells is developing mutations and errors that are generally handled by machinery within your cells, but ultraviolet rays from the Sun lead to mutations that the cell may not be able to overcome, leading to uncontrolled growth and eventual skin cancer.

紫外線B波で日焼けすることは知られていますね。

The scariest thing about this is that usually you can't even see it happening until its too late.

紫外線A波の働きはあまり理解されておらず

But if these concrete risks to your health are not enough to convince you to use sunscreen, there are aesthetic reasons as well.

どうやら

Along with cigarette smoking, sun damage is the leading cause of premature aging.

日焼けへの反応、

Photoaging from chronic sun exposure leads to a loss of elasticity in the skin, in other words, making it look saggy.

発がん現象、

Take a look at this truck driver who's left side was chronically exposed to the sun and notice the difference.

老化に影響するようです。

This is an important point.

日焼け止めは、これらの光線から私たちをどう守ってくれるのでしょう？

Car windows block UVB, the burn rays, but not UVA, the aging rays.

日焼け止めの基本的タイプには2種類あり、

It is recommended to use sunscreen daily, but you should pay special attention before prolonged sun exposure or when at the beach or among snow since the reflectivity of water and ice amplifies the Sun's rays.

物理的な遮断と化学的な遮断です。

For these cases, apply about an ounce fifteen to thirty minutes before you go out and once again soon after you get outside.

物理的なものは酸化亜鉛や

After that, you should reapply it every two to three hours, especially after swimming or sweating.

二酸化チタンで

Otherwise you should wear protective clothing with ultraviolet protection factor, or UPF.

物理的なバリアとして機能することで、太陽光線を反射します。

Stay in shaded areas, such as under trees or an umbrella, and avoid the sun at the peak hours of 10 a.m. to 4 p.m.

鼻が白くなっているライフガードを見たことがあるなら

And what's the best kind of sunscreen?

これがどんなものか分かるでしょう。

Everyone will have their preference, but look for the following things: broad spectra, SPF of at least 30, and water-resistant.

同じ原料は、おむつかぶれ用クリームの主成分にも

A light moisturizer with SPF 30 should be good for daily use.

なっていて

Take note if you decide to use a spray.

これも物理的なバリアを作ろうとするものです。

They take several coats to effectively cover your skin, like painting a wall with a spray can versus a paint brush.

昔はこれを塗るのがそう簡単ではなく肌の上で目立ってしまっていましたが新処方により、これは解決されつつあります。

So, enjoy the sun, but enjoy it with sunscreen.

一方、化学的なものは