and some of us are addicted to. If you are a caffeine user, you probably know your limits.

和我們中的一些人上癮。如果你是一個咖啡因使用者，你可能知道你的極限。

For me one small cup of coffee in the morning can help keep me alert and focused, whereas

對我來說，早上一小杯咖啡可以幫助我保持警覺和集中精力，而

two small cups of coffee in the morning can turn me into a cat on catnip.

早上喝兩小杯咖啡就能把我變成一隻吃貓薄荷的貓。

Well for the purposes of this video and to best demonstrate the physical and mental effects of caffeine,

好吧，為了這段視頻的目的，也為了最好地展示咖啡因的生理和心理作用。

I'm going to get

我將會得到

very very caffeinated very very fast.

非常非常咖啡因的非常非常快。

For science.

對於科學：

Go big or go home.

要麼大幹一場，要麼回家。

Caffeine is a stimulant drug that acts on your central nervous system.

咖啡因是一種對中樞神經系統起作用的刺激性藥物。

Because caffeine is both lipid and water soluble

因為咖啡因既是脂質又是水溶性的。

it can easily pass through the blood-brain barrier and act on the interior of your brain

它可以很容易地通過血腦屏障並作用於你的大腦內部。

Once there, caffeine works by diminishing the effect of a neurotransmitter called adenosine.

一旦到了那裡，咖啡因就會通過減少一種叫做腺苷的神經遞質的作用來發揮作用。

Adenosine acts as a suppressor for your nervous system,

腺苷作為神經系統的抑制劑。

reducing neural activity and slowing everything down.

減少神經活動，讓一切都慢下來。

Caffeine and adenosine have similar shapes so caffeine can bind to

咖啡因和腺苷有相似的形狀，所以咖啡因可以結合到

the same neuroreceptors that adenosine does.

和腺苷一樣的神經感受器。

But because caffeine is not adenosine, it doesn't turn these neuroreceptors on.

但因為咖啡因不是腺苷，所以它不會把這些神經受體打開。

This is called competitive inhibition.

這就是所謂的競爭性抑制。

Caffeine competes with adenosine to bind with the same receptors,

咖啡因與腺苷競爭，與相同的受體結合。

And because caffeine is bound, adenosine cannot bind and its effects are inhibited.

而由於咖啡因被結合，腺苷不能結合，其作用被抑制。

Long story short,

長話短說。

caffeine prevents adenosine from slowing down your nervous system.

咖啡因可以防止腺苷減緩你的神經系統。

So this explain part of why you feel more awake, alert and active with caffeine flowing through your veins.

是以，這解釋了為什麼你覺得更清醒，警惕和活躍的咖啡因流經你的靜脈的一部分。

But adenosine inhibition isn't the only thing that caffeine does.

但腺苷抑制並不是咖啡因的唯一作用。

Oh no.

哦，不。

Caffeine also stimulates the production of adrenaline or epinephrine.

咖啡因還能刺激腎上腺素或腎上腺素的產生。

Adrenaline is a pretty well known hormone involved in the fight-or-flight response.

腎上腺素是一種相當知名的激素，參與戰鬥或飛行反應。

It causes all sort of physiological reactions! It increases your heart rate,

它能引起各種生理反應!它能增加你的心率。

increases the blood flow to your muscles,

增加肌肉的血液流動。

opens up your airways, causes your blood pressure to rise, and also causes you're

打開你的呼吸道，導致你的血壓上升，也會導致你'。

your liver to release extra sugar into your blood stream for an added boost of energy.

你的肝臟會釋放額外的糖分到血液中，以增加能量。

It also causes your muscle to tighten up,

它還會使你的肌肉變得緊實。

which would be useful if you were the lone human on the savannah,

這將是有用的，如果你是 孤獨的人類在大草原上。

deciding or not to fight or flee from that lion over the distance,

決定是否與那頭獅子戰鬥或遠距離逃跑。

But as a modern twenty something sitting in from of my camera, it just give me the jitters.

但作為一個二十多歲的現代人，坐在我的相機前，它只是讓我感到不安。

Finally caffeine also plays with the dopamine levels in your brain.

最後咖啡因還能發揮你大腦中的多巴胺水準。

Awesome, yeah.

真棒，是的。

Caffeine increases the amount of dopamine present in your brain by slowing down its reabsorption,

咖啡因通過減緩大腦對多巴胺的重吸收來增加大腦中存在的多巴胺數量。

Much in the same way that cocaine increases the amount of dopamine present

就像可卡因會增加多巴胺的含量一樣。

by slowing down how quickly it can be sucked back into your brain tissue.

通過減慢它被吸回腦組織的速度。

This means that caffeine also makes you feel good and this interaction with dopamine is how you can actually

這意味著咖啡因也會讓你感覺良好，而這種與多巴胺的相互作用是如何讓你真正的

build a caffeine addiction. So now you're a happy,

建立一個咖啡因癮。所以現在你'是一個快樂的。

jittery, fight or flight ready bundle caffeine! Now what?

焦躁不安，戰鬥或飛行準備捆綁咖啡因!現在怎麼辦？

Well the now what really depends on how your specific body metabolizes caffeine.

好了現在什麼真的取決於你的具體身體如何代謝咖啡因。

The average half-life of caffeine in the human body is about six hours.

咖啡因在人體內的平均半衰期約為6小時。

so this means that if you have two hundred milligrams of caffeine in your average cup of coffee at 9am in the morning,

所以，這意味著，如果你有200毫克的咖啡因 在你的平均杯咖啡在上午9點。

then 6 hours later half of that will be left, so at 3pm

然後6小時後將剩下一半，所以在下午3時

you will have a hundred milligrams of caffeine left, and then another 6 hours later you will have half of the hundred

你將有一個百毫克的咖啡因左， 然後另一個6小時後，你將有一半的百。

you will have half of the hundred so you will have 50 milligrams of caffeine left at 9 o'clock at night.

你將有一半的百，所以你將有50毫克的咖啡因留在晚上9點'鍾。

But dude, who stops at just one cup of coffee?

但是，老兄，誰會只喝了一杯咖啡就停下來呢？

Not this chick. So how much caffeine is too much caffeine?

不是這個小妞。那麼，多少咖啡因才算太多？

A lethal dose of caffeine is about two hundred milligrams per kilogram

致命的咖啡因劑量是每公斤兩百毫克左右。

so it would take about nine thousand five hundred milligrams of caffeine to kill me.

是以，它將採取約 9000 500毫克 咖啡因殺了我。

Now, there are about two hundred milligrams of caffeine in a standard cup of coffee,

現在，一杯標準的咖啡中大約有兩百毫克的咖啡因。

so that's about forty eight cups of coffee,

所以，這是大約四十八杯咖啡。

which is a surprisingly low number, but I would have to drink

這是個令人驚訝的數字，但我必須飲用

all 48 of those before my body started to metabolize the caffeine,

所有48個之前，我的身體 開始代謝咖啡因。

which means I would literally have to chug 48 cups of coffee.

這意味著我將從字面上有 嗆48杯咖啡。

I literally wouldn't be able to drink that much coffee,

我真的不會喝那麼多咖啡。

both because my stomach couldn't hold that volume of liquid and also because as every coffee drinker knows,

都是因為我的胃不能容納那捲液體，還因為每個喝咖啡的人都知道。

caffeine is a diuretic.

咖啡因是一種利尿劑。

before I got to cup forty anyways, the stimulant effect of caffeine would be

在我拿到40杯之前，無論如何，咖啡因的刺激作用將是。

jacked up so high that that the alertness and awakeness would be transformed into mania,

抬高了，以至於警覺性和覺醒性會轉化為狂躁。

disorientation and hallucinations... great!

迷失方向和幻覺... ...好極了!

What would eventually kill you would be ventricular fibrillation, which basically means

最終會要了你的命的是心室顫動，這基本上是指：

that your heart would caffeine jitter itself to death.

你的心臟會因咖啡因抖動而死亡。

So moral of the story, caffeine is a drug. It is a stimulant that has some pretty noticeable effects on your body,

所以故事的寓意是，咖啡因是一種藥物。它是一種興奮劑，對你的身體有一些非常明顯的影響。

can cause addiction, and, in high enough doses, can kill you.

可以導致上癮，並且，在足夠高的劑量，可以殺死你。

So caffeinate wisely!

所以，明智地喝咖啡吧！

Go forth, do science!

去吧，做科學！

My hand is actually not shaking too bad right now.

其實我的手現在抖得並不厲害。

Don't try this at home, I know a lot of people do drink that much caffeine all on one day and

不要'不嘗試在家裡，我知道很多人做喝那麼多的咖啡因所有在一天和

sometimes I approach it,

有時我接近它。

but I certainly don't do it over the span of 20 minutes.

但我肯定不會在20分鐘內完成。

I actually don't feel as terrible as I thought I would have after that amount, but I certainly don't feel good either.

其實，我覺得我沒有想象中的那麼可怕，我想我會有後，但我肯定不'感覺好也。