And good hygiene is how we protect ourselves from infections and the social stigma of being smelly.

保持良好的衛生是我們保護自己免於感染和因發臭而成為社會恥辱的方式。

But do you really need a daily shower to stay clean, or is it doing more harm than good?

但你是否真的需要每天淋浴以保持清潔，還是這其實弊大於利呢？

Turns out there aren't any definite rules, but some scientists have recommendations based on what we know about the biology of our skin, and what might be living on top of it.

事實是，沒有明確規範，但是一些科學家根據我們對皮膚構造的了解以及什麼可能存活於皮膚上的生物而提出了建議。

Your skin is a giant organ that physically blocks harmful stuff from getting inside your body.

你的皮膚是一個巨大的器官，可以從實質上阻止有害物質進入體內。

It's covered in a bustling community of bacteria, fungi, viruses, and even teeny-tiny arthropods.

皮膚上佈滿了群集的細菌、黴菌、病毒，甚至微小的節肢動物。

They make up what's known as your skin microbiome.

牠們構成了所謂的皮膚微生物群。

For the most part, researchers think that these microbes you carry with you are pretty harmless.

研究人員認為在多數情況下，人體攜帶的這些微生物是無害的。

But as you interact with the world, you can pick up other microbes that could make you sick.

但在進行各種互動時，你可能會沾染到其他讓你感到不適的微生物。

And when you, like, rub your eyes or put food in your mouth, your hands can help those germs slip past your skin and get into your body.

而當你揉眼睛或把食物放入口中，你的手會助長這些細菌躲過皮膚並進入體內。

Which is why washing your hands with soap is so important, especially if you work in medicine or food service.

這就是用肥皂洗手的重要性，尤其如果你是從事醫療或食品服務業的工作。

See, soap is a surfactant, which means it's made of molecules that can bind to water and things like dirt, oils, or bacteria.

要知道肥皂是一種表面活性劑，意味著它是由可以與水和汙垢、油脂或細菌等物質結合的分子所組成。

This lets you rinse all that junk away, and fewer germs means a lower chance of infections.

這讓你可以沖洗掉所有穢物，而細菌量的減少則代表感染的機會也會降低。

But what about washing the rest of your body?

但是清洗身體其他部位要怎麼做呢？

Well, your skin has glands that are always producing sweat and oils, which cools you down and keeps your skin moisturized and healthy.

這個嘛，你皮膚上的腺體會持續分泌汗水和油脂，以冷卻皮膚並讓其保持濕潤和健康。

But there is a fine balance.

但這之中有一個精密的平衡點。

Certain bacteria break down sweat and release smelly molecules like thioalcohols.

某些細菌會分解汗液，並釋放出像硫醇這樣有氣味的分子。

And if your skin has too much dirt, dead skin cells, or oils, your pores can get clogged, leading to problems like acne.

而如果你的皮膚上有太多污垢、死皮細胞或油脂，毛孔可能會阻塞，導致青春痘之類的皮膚問題。

So showering with soap can help get rid of some sweat and oil to manage your looks and smell.

因此，洗澡時使用肥皂有助於去除一些汗水和油脂，以控管你的外貌和體味。

And in some cases, like the night before a surgery, a doctor might tell you to shower with an antimicrobial soap, which has extra chemicals to kill microbes.

在某些情況下，例如手術前一晚，醫生可能會要你用抗菌肥皂洗澡，這種肥皂中添加了足以殺死微生物的化學物質。

If a surgeon is making cuts in your skin, they don't want any potentially dangerous stuff sneaking in.

如果外科醫生必須切割你的皮膚，他們不會希望任何潛在的危險物質滲入。

On the other hand, showering too often might not be great for you either.

另一方面，太常洗澡對你可能也不太好。

For one, it can mess with the microbes that naturally live on your skin.

首先，頻繁洗澡會影響皮膚表層自然存在的微生物。

And since soap and water wash away oils, your skin might get too dry so the outer layer cracks, making it easier for disease-causing microbes to slip into your body.

由於肥皂和水會洗去油脂，你的皮膚可能會變得太乾而破裂，使得致病微生物更容易溜進體內。

So, dermatologists seem to say that daily showers where you scrub everywhere with soap is probably overkill, unless you sweat a lot, like people who work out every day.

因此，皮膚科醫生似乎都認為每天淋浴都用肥皂洗淨全身可能過當，除非你跟每天健身的人一樣常流汗。

Otherwise, showering every couple of days should be just fine to keep your skin microbiome healthy and happy.

否則，隔幾天洗一次澡應該無妨，也可以保持皮膚微生物群系健康快樂。

Thanks to our Patreon patrons for asking this question.

感謝「合作夥伴」贊助者的發問。

If you want to learn more about health-related topics, check out our sister channel, Healthcare Triage, hosted by Dr. Aaron Carroll.

如果你想多了解健康相關的主題，請收看我們的姐妹頻道、由 Aaron Carroll 博士主持的 Healthcare Triage。

And don't forget to go to youtube.com/scishow and subscribe!

別忘了收看 youtube.com/scishow 並訂閱頻道！