It turns out fever is one of the oldest defenses against disease.

原來，發燒是最古老的防病手段之一。

What exactly is it, how does it make your immune defense stronger, and should you take a pill to combat it?

它到底是什麼，如何讓你的免疫防禦能力更強，你是否應該吃藥來對付它？

The heat of life.

生命之熱

On Earth, life is able to thrive between the extremes of minus 10 degrees Celsius in deep cool pools, and 120 degrees Celsius in thermal vents.

在地球上，生命能夠在零下 10 攝氏度的深冷水池和 120 攝氏度的熱噴口等極端環境中繁衍生息。

Step outside this range and die.

超出這個範圍就會死亡。

Every animal or microbe has a temperature range that's ideal, and one that's stressful, but survivable for a while.

每種動物或微生物都有一個理想的溫度範圍，也有一個壓力較大但可以暫時存活的溫度範圍。

Your ideal temperature is where your cells work best, where their internal machinery is the most efficient, and the animal as a whole the best adapted to its niche.

理想的溫度是細胞工作得最好的地方，也是內部機器效率最高的地方，更是整個動物最適合其生存環境的地方。

Humans are warm-blooded animals, and our bodies expand a lot of energy to keep us around 37 degrees Celsius or 98.6 degrees Fahrenheit.

人類是溫血動物，我們的身體需要消耗大量能量，才能將溫度保持在攝氏 37 度或華氏 98.6 度左右。

Which seems wasteful, but this may actually be a defensive adaptation.

這似乎有些浪費，但實際上這可能是一種防禦性調整。

Our temperature makes us almost entirely immune to one of the worst killers and parasites, fungi.

我們的體溫使我們對最可怕的殺手和寄生蟲之一--真菌幾乎完全免疫。

Most colder animals and their insides are infected by them, but you are just too hot.

大多數較冷的動物及其內臟都會受到它們的感染，但你實在是太熱了。

Which brings us to fever.

這讓我們想到了發燒。

For any microbe that wants to infect you, your body is a world they want to conquer.

對於任何想要感染你的微生物來說，你的身體就是它們想要征服的世界。

Fever is defensive climate change, pushing an invader outside its ideal temperature range and making the world horrible.

發燒是防禦性氣候變化，把入侵者推到理想溫度範圍之外，讓世界變得可怕。

It evolved at least 600 million years ago and is widespread.

它至少在 6 億年前進化而來，分佈廣泛。

Most animals increase their core temperature when they're sick.

大多數動物在生病時核心體溫都會升高。

Fish swim into warmer waters, lizards bathe in the sun, bees heat up the air inside their hive.

魚兒遊入更溫暖的水域，蜥蜴沐浴在陽光下，蜜蜂將蜂巢內的空氣加熱。

But you, warm-blooded mammal, you have way more drastic options.

但是你，溫血哺乳動物，你有更激烈的選擇。

Let's make you sick and see what happens.

讓我們讓你生病，看看會發生什麼。

When your blood turns into lava.

當你的血液變成岩漿

You're invaded by bacteria and viruses at the same time.

細菌和病毒同時入侵你的身體。

The invasion is powerful, and you need to slow it down as fast as possible.

入侵者的力量很強大，你需要儘快減緩它的速度。

Fever is part of your first line of defense, triggered by a diverse group of chemicals called pyrogens, the creators of heat.

發燒是人體第一道防線的一部分，是由一組名為 "熱原 "的多種化學物質引發的。

They float away from the battlefield and pass right into your brain, where specialized receptors pick them up and crank up your internal thermostat.

它們飄離戰場，直接進入你的大腦，在那裡，專門的受體會捕捉到它們，並調高你體內的恆溫器。

First you begin to shiver.

首先，你開始顫抖。

Your skeletal muscles contract really quickly, which generates a lot of heat in your core.

骨骼肌會快速收縮，從而在核心部位產生大量熱量。

At the same time, usually the blood vessels near your surfaces contract and prevent heat from escaping through your skin.

與此同時，您體表附近的血管通常會收縮，防止熱量通過皮膚散發。

Your skin cools down while your insides burn.

你的皮膚在冷卻，而你的內心卻在燃燒。

Fever is a systemic, body-wide response and is a serious energy investment for your body.

發燒是一種全身性的全身反應，對身體來說是一種嚴重的能量投資。

You burn about 10% more calories to stay alive for every degree centigrade your body temperature rises.

體溫每升高 1 攝氏度，為維持生命而消耗的熱量就會增加 10%。

Fever is also a strong order to lay down and rest, to save energy and give your immune system time to fight.

發燒也是一種強烈的命令，讓你躺下休息，以保存體力，讓免疫系統有時間戰鬥。

Back to the battlefield.

回到戰場

When the bacteria entered your body, they tried to be stealthy, but now they've switched into high-production mode.

當細菌進入你的身體時，它們試圖保持隱祕，但現在它們已轉入高產模式。

Their goal is to multiply as fast as possible, which means they need a lot of resources and are highly stressed.

它們的目標是儘可能快地繁殖，這意味著它們需要大量資源，壓力很大。

Imagine running a marathon while eating a succulent Chinese meal and giving birth.

想象一下，一邊跑馬拉松，一邊吃著豐盛的中餐，一邊分娩。

The last thing bacteria need right now is more stress.

細菌現在最不需要的就是更多的壓力。

So your immune system tries to stress them out as much as possible by ordering inflammation, which floods the battlefield with fluids, attack proteins and soldiers.

是以，您的免疫系統試圖通過發炎來儘可能地給它們施加壓力，讓體液、攻擊蛋白和阿兵哥充斥戰場。

Pretty stressful.

壓力很大

Fever is even more stress.

發燒更是一種壓力。

For the bacteria a moment ago, the temperature range was pleasant.

對於剛才的細菌來說，溫度範圍是令人愉快的。

Now the world burns.

現在，世界在燃燒。

Heat can cause their organs to break and membranes to rupture, damage their DNA and diminish protein production.

熱量會導致它們的器官破裂、膜破裂、DNA受損和蛋白質生產減少。

They are seriously suffering from the heat.

他們正遭受著高溫的嚴重摺磨。

Why doesn't this affect your cells?

為什麼這不會影響你的細胞？

It does.

確實如此。

All of this is stressful for your cells too.

所有這些也會給細胞帶來壓力。

Virtually every system and organ of your body works worse during fever, except one, your immune system.

發燒時，身體的每個系統和器官幾乎都會工作得更糟糕，只有一個例外，那就是免疫系統。

Cells are recruited faster, macrophages and dendritic cells are better at devouring enemies, killer cells kill better, and so on.

細胞招募速度更快，巨噬細胞和樹突狀細胞吞噬敵人的能力更強，殺傷細胞的殺傷力更強，等等。

And fever animates your immune cells to gobble up the critical resources your enemies need like iron, glucose and glutamine, turning the battlefield into a food desert.

發燒會激發免疫細胞吞噬敵人所需的重要資源，如鐵、葡萄糖和谷氨醯胺，使戰場變成食物沙漠。

The viruses that infected millions of cells are doing even worse because they are also very sensitive to heat.

感染了數百萬個細胞的病毒情況更糟，因為它們對熱也非常敏感。

For example, the rhinovirus that causes the common cold can only infect your respiratory tract because it is significantly colder than the rest of your body, even without fever.

例如，引起普通感冒的鼻病毒只能感染呼吸道，因為即使不發燒，呼吸道也比身體其他部位冷得多。

The heat is also really bad for the millions of cells that are infected by viruses at this point.

此時，高溫對數百萬個受病毒感染的細胞也非常不利。

They are working super hard producing viruses, which is pretty stressful.

他們正在超負荷地生產病毒，壓力相當大。

As the heat becomes too much to bear, the super stressed cells panic.

當熱量變得難以承受時，壓力過大的細胞就會驚慌失措。

As their internal machinery is breaking and failing, they quickly produce billions of heat shock proteins, or HSPs, that start repairs, keeping them alive.

當它們的內部機制正在崩潰和失效時，它們會迅速產生數十億熱休克蛋白（或 HSPs），開始進行修復，從而維持它們的生命。

But this is a trap.

但這是一個陷阱。

Even your healthy cells produce HSPs to deal with the heat, but if a cell makes too many of them, this means it's more stressed than it should be.

即使是健康的細胞也會產生 HSPs 來應對高溫，但如果細胞產生過多的 HSPs，就意味著它受到的壓力超過了應有的水準。

And if it's too stressed, something is wrong and it should be killed.

如果壓力過大，就說明出了問題，應該把它殺掉。

So your natural killer cells and killer T-cells are activated and attracted by HSPs and start killing infected cells and all the viruses inside them.

是以，你的自然殺傷細胞和殺傷性 T 細胞會被 HSPs 激活和吸引，並開始殺死受感染的細胞和其中的所有病毒。

By trying to protect themselves, infected cells are calling out to be destroyed.

受感染的細胞試圖保護自己，從而要求被摧毀。

But if fever is such an effective weapon, why don't your enemies adapt to it?

但是，如果發燒是一種如此有效的武器，為什麼你的敵人不適應它呢？

How is it still viable in so many different animals after hundreds of millions of years?

經過數億年之後，它為何仍能在這麼多不同的動物體內存活？

A wild reason is that fever actually might outsmart evolution.

一個瘋狂的理由是，發燒實際上可能比進化更聰明。

If your enemies survive fever long enough, natural selection changes them.

如果你的敵人在高燒中存活的時間足夠長，自然選擇就會改變他們。

The individuals that are better suited to deal with heat reproduce more.

更適合應對高溫的人繁殖得更多。

After a few days, they've adapted.

幾天後，它們就適應了。

But this becomes a handicap because the next step is to infect new victims in new bodies, and now healthy humans are too cold for them.

但這也成了一種障礙，因為下一步就是在新的身體裡感染新的受害者，而現在健康的人類對它們來說太冷了。

Not impossible to infect, just harder.

並非無法感染，只是更難感染。

And the heat-resistant microbes now compete with their cousins that like it colder and have an advantage infecting healthy hosts.

現在，耐熱微生物與喜歡寒冷的表親競爭，在感染健康宿主方面佔據優勢。

This creates an evolutionary dilemma without a perfect solution.

這就造成了一種進化困境，沒有完美的解決方案。

To circumvent this, serious pathogens like measles use hit-and-run tactics.

為了規避這一問題，麻疹等嚴重病原體會採取 "打了就跑 "的策略。

The measles virus is the most infectious right before your fever hits with full force.

麻疹病毒在發燒前傳染性最強。

It's brutally beaten back once your full immune response shows up, but by then, the damage is done.

一旦你的免疫反應完全顯示出來，它就會被殘酷地擊退，但那時，傷害已經造成。

Fever is an effective part of the puzzle of your immune system, helping to attack and stress your enemies from as many angles as possible.

發燒是免疫系統拼圖的一個有效組成部分，有助於從儘可能多的角度攻擊敵人，給敵人造成壓力。

But if fever is so great, why do we stop it when we're sick?

但是，如果發燒這麼厲害，為什麼我們生病時還要停止發燒呢？

Should you fight fever with medications?

應該用藥物退燒嗎？

We think it's normal to have magic pills, but relatively harmless, over-the-counter pain medication like aspirin or ibuprofen only became cheap and widely available in the last century or so.

我們認為擁有靈丹妙藥很正常，但阿司匹林或布洛芬等相對無害的非處方止痛藥只是在上個世紀左右才變得廉價和廣泛。

Going to a pharmacy to get something for your headache is extremely new in human history.

去藥店買藥治頭痛，這在人類歷史上還是頭一遭。

Pain feels bad, so we've gotten used to stopping it when we feel it.

疼痛的感覺很糟糕，所以我們已經習慣了在感覺到疼痛時就停止疼痛。

If you're sick, you're supposed to feel a reasonable amount of pain so you lie down and save energy.

如果你生病了，你應該感到適度的疼痛，這樣你就會躺下，節省體力。

This is not a bug, but a feature of your immune system.

這不是毛病，而是免疫系統的一個特徵。

But pain and fever are closely connected, and over-the-counter pain medication like ibuprofen and paracetamol also work against fever.

但疼痛和發燒密切相關，布洛芬和撲熱息痛等非處方止痛藥也有退燒作用。

Especially in children, fever is often suppressed by worried parents or doctors, sometimes because they think fever itself is the disease, or they're worried that it can do long-term harm.

特別是在兒童身上，發燒常常被憂心忡忡的家長或醫生壓制下去，有時是因為他們認為發燒本身就是疾病，或者擔心發燒會造成長期傷害。

In general, it's fair to say that for temperatures below 40°C or 104°F, fever is not dangerous and doesn't need to be treated.

一般來說，如果體溫低於 40°C 或 104°F，發燒並不危險，也無需治療。

Of course, there are also patients that should not have fever, like pregnant women, seniors, and seriously weakened patients.

當然，也有一些病人不應該發燒，比如孕婦、老年人和嚴重虛弱的病人。

For them, the extra stress may be dangerous.

對他們來說，額外的壓力可能是危險的。

Temperature over 40°C is dangerous to anybody, because it's most likely caused by your internal heat monitor failing.

溫度超過 40°C 對任何人來說都是危險的，因為這很可能是由於內部熱監控器發生故障。

Things get more complicated in serious disease territory.

在重病領域，情況會變得更加複雜。

We also have evidence that for some diseases like influenza or chickenpox, anti-fever drugs do not help you to heal faster, but we're also running into ethics problems here that make clinical trials difficult.

我們也有證據表明，對於某些疾病，如流感或水痘，退燒藥並不能幫助你更快地痊癒，但我們也遇到了倫理問題，使臨床試驗變得困難重重。

In one study, doctors gave strong anti-fever treatment to critical care patients, but had to stop after mortality shot up.

在一項研究中，醫生為危重病人提供了強效退燒治療，但在死亡率飆升後不得不停止。

Overall, we have strong indications that more people may survive serious infectious diseases better with a fever, and there is very little clinical evidence that stopping fever leads to better health outcomes.

總之，我們有強烈的跡象表明，發燒時更多的人可能會在嚴重傳染病中存活得更好，而很少有臨床證據表明退燒會帶來更好的健康結果。

But there are important exceptions, like neurological injuries and stroke.

但也有一些重要的例外情況，比如神經損傷和中風。

We definitely need a lot more research.

我們肯定需要更多的研究。

So should you fight fever?

那麼，你應該退燒嗎？

Well, speak to your doctor, and don't listen to internet videos.

那就去問醫生，別聽信網絡視頻。

But this decision is really about payoffs.

但這個決定實際上是關於回報的。

If a fever is not dangerously high, and you can bear it, you're supporting your defences, and may even get healthy a bit faster.

如果發燒沒有達到危險的程度，而你又能忍受，那麼你就是在支持自己的防禦，甚至可能會更快地恢復健康。

But if you feel really bad and are healthy in general, taking a pill against pain and fever will make you feel better quicker, at the cost of a slightly less effective immune defence.

但是，如果你感覺非常糟糕，而且身體健康，服用止痛退燒藥會讓你更快好起來，但代價是你的免疫防禦能力會稍差一些。

However you decide, the next time you're burning up and feeling bad, you can rest easy in the knowledge that your enemies are having a much worse time than you.

無論你做出怎樣的決定，下次當你焦頭爛額、心情糟糕時，你就可以高枕無憂了，因為你知道你的敵人過得比你更糟糕。

It's thanks to doctors and researchers that we have these insights, we're just doing our part by bringing them to you.

多虧了醫生和研究人員，我們才有了這些真知灼見，我們只是儘自己的一份力，把它們帶給大家。

If you are also aiming to make a positive difference in the world, where should you start?

如果您也希望給世界帶來積極的變化，您應該從哪裡開始呢？

Today's sponsor 80,000 hours can help you with that decision.

今天的贊助商 80,000 小時可以幫助您做出決定。

80,000 hours is a non-profit career advice organisation that wants to help people find fulfilling careers that also do a lot of good in the world.

80,000 小時 "是一個非營利性職業諮詢組織，希望幫助人們找到充實的職業，同時也為世界做很多好事。

And their advice is free, without any hidden cost or fee later on.

而且他們的建議是免費的，沒有任何隱藏成本或後續費用。

Because they care a lot about making sure their work is based on the best available evidence and consultation with experts.

因為他們非常注重確保自己的工作以現有的最佳證據和專家諮詢為基礎。

So they've spent the last decade compiling and conducting research into topics like how much impact can one person actually have?

是以，他們花了十年時間對一些主題進行了彙編和研究，比如一個人究竟能產生多大的影響？

And what are the best ways to make a positive difference on important global issues?

在重要的全球性問題上發揮積極作用的最佳方式是什麼？

Turns out following a well-known career path isn't your only option to achieve that goal.

事實證明，追隨一條眾所周知的職業道路並不是實現這一目標的唯一選擇。

In fact, there may be many paths that make an even bigger difference in the world that you may not have even heard of.

事實上，可能有很多道路會給世界帶來更大的變化，而這些道路你可能聞所未聞。

The time you'll spend on your career is probably your biggest opportunity to have an impact.

你在職業生涯中花費的時間可能是你產生影響的最大機會。

If you want to make the most of it, join the newsletter now and get a free copy of their in-depth career guide sent to your inbox.

如果您想充分利用它，現在就加入時事通訊，免費獲得一份發送到您收件箱的深度職業指南。

Just sign up at 80,000hours.org slash in-a-nut-shell.

只需登錄 80,000hours.org slash in-a-nut-shell 註冊即可。

Are you scared of AI taking over?

你害怕人工智能接管一切嗎？

We've got what you need.

我們能滿足您的需求。

A survival kit for the future.

未來的生存工具包

And it's dropping at this very moment.

而此時此刻，它正在下降。

Come closer.

靠近點

Don't be shy.

別害羞

We'll show you what you need to do.

我們會告訴你需要做什麼。

First, the sock problem.

首先是襪子問題。

You've heard of it.

你一定聽說過。

One of your socks will always slip into another dimension at one point, never to be found again.

你的一隻襪子總會在某個時刻滑落到另一個空間，再也找不到了。

So we've solved this once and for all.

是以，我們一勞永逸地解決了這個問題。

A pair of three different socks.

一雙三種不同的襪子

Lose one and still be fine.

丟掉一個也沒事。

Now complete your future-proof outfit and put on this amazing shirt to show everyone that you embrace the digital revolution.

現在，穿上這件神奇的襯衫，向所有人展示你擁抱數字革命的決心，完成你面向未來的裝備吧。

Next, you should create an analogue backup of your best ideas.

接下來，你應該為你的最佳創意創建一個模擬備份。

This tiny notebook is 100% AI-proof and will keep your thoughts safe from any digital super-being.

這款小巧的筆記本 100％ 防人工智能，能保護你的思想不受任何數字超級生物的影響。

And of course, you can't forget to bring a towel.

當然，你也不能忘記帶一條毛巾。

You can lie on it, sleep under it, or wave it in emergencies as a distress signal.

你可以躺在上面，睡在下面，或者在緊急情況下揮舞它作為求救信號。

It also contains an accurate map of the entire universe so you won't get lost.

它還包含整個宇宙的精確地圖，讓你不會迷路。

Or you can, you know, dry yourself off with it.

你也可以用它來擦乾身體。

If you want to get a glimpse of what's to come in the future, get this portal, um, poster.

如果你想一睹未來的風采，那就來看看這個門戶網站，嗯，海報。

But beware, not everything is as it seems.

但要注意，並非所有事情都像看上去那樣。

Visit our shop and gear up.

訪問我們的商店，準備裝備。

We recommend getting the entire survival kit just to be safe and save money.

為了安全和省錢，我們建議購買一整套生存工具包。

All of our products are designed and produced with love and care by us here at Kurzgesagt.

我們的所有產品都是由 Kurzgesagt 精心設計和生產的。

Like with our last limited drop, these items are available now until they sell out and then never again.

和上次的限量發售一樣，這些商品從現在開始發售，直到售罄為止，之後再也不會發售。

But these products don't just ensure your survival, they also protect the future of

但是，這些產品不僅能確保您的生存，還能保護以下國家的未來

Kurzgesagt.

Kurzgesagt.

Every single product you buy supports everything we do on this channel and enables us to release our videos for free for everyone.

您購買的每一件產品都會支持我們在這個頻道上所做的一切，並使我們能夠免費向所有人發佈我們的視頻。

Thank you so much for your support.

非常感謝你們的支持。

There would be no future of Kurzgesagt without you.

沒有你們，就沒有 Kurzgesagt 的未來。