And I love coffee.

我愛喝咖啡。

The intoxicating nutty aroma.

令人上癮的堅果香氣。

The rich chocolatey taste.

厚實的巧克力滋味。

Some days, I drink three cups, like the average American I am.

有時候我一天喝三杯咖啡，跟一般的美國人一樣。

Other days, I drink more like five or six.

有些時候我會喝到五或六杯。

But is that too much?

這樣會太多嗎？

First, the good news.

先從好消息說起。

It's almost impossible to overdose on coffee.

咖啡幾乎不可能攝取過量。

There is a lethal dose of caffeine, but it's somewhere around 10 grams, and the average cup of joe has around 100 milligrams.

咖啡因攝取達一定程度確實會致命，但你得喝到10公克；我們一般喝的咖啡一杯只有100毫克。

So, you'd likely have to drink 100 cups in rapid succession to OD.

你大概得連續喝上100杯才算過量。

But that's not to say there's no such thing as too much.

不過這並不代表你可以想喝幾杯就喝幾杯。

The FDA recommends no more than four to five cups a day for the average healthy adult.

根據美國食品藥品監督管理局建議，一般健康的成年人一天不要喝超過四或五杯。

More than that, and you might start to experience some nasty side effects.

超過該建議量，你可能會開始出現嚴重的副作用。

You know, most people take in ca⏤coffee for, you know, to... increase their focus and their concentration.

多數人喝咖啡是為了提高注意力、專注程度。

Uh, once you start, you know, taking in too much, uh, you start losing that focus.

一旦喝太多，你反而會流失注意力。

People start getting more agitated, irritable.

人們會變得躁動不安、易怒。

That's thanks to the hormone, adrenaline.

這是因為腎上腺素這種荷爾蒙所導致。

When caffeine hits your system, it stimulates your adrenal glands, which release the hormone into your body.

當咖啡因流入你的身體，它會刺激腎上腺體，將荷爾蒙釋放至你體內。

It makes you feel energetic and alert, perfect for a fight-or-flight situation.

它會讓你充滿活力、提高警覺，遇上「戰或逃」的緊急狀況會很有幫助。

But too much can be a bad thing, especially if you suffer from anxiety.

但喝太多就會變成壞事，尤其是如果你本身就有焦慮問題。

But, with anxiety, you also wanna be... be careful, uh, not to, you know, overstimulate it or trigger any sort of panic attacks or, you know, would make things, uh, this anxiety worse, which, certainly, too much caffeine can do.

說到焦慮症，要小心不能過度刺激，不能誘發任何型態的恐慌感，這會讓焦慮症惡化，而太多咖啡因絕對會造成這種情況。

Adrenaline from caffeine can also increase your heart rate.

咖啡因激起的腎上腺素也會使你的心跳加速。

That's why doctors often recommend against drinking coffee if your heart sometimes beats irregularly.

這就是為什麼醫生通常會建議有心跳不規律的人不要喝咖啡。

But the risk is really only for bona fide coffee junkies.

然而這樣的風險只針對真正的咖啡上癮者。

According to at least two observational studies, you have to drink at least nine cups of coffee a day to put yourself at risk of arrhythmia.

根據至少兩項觀察研究，你一天得喝超過九杯咖啡才可能害自己心律不整。

And, finally, there's the question of sleep, coffee's enemy.

最後，是睡眠的問題，咖啡的敵人。

Caffeine launches a double threat on your slumber.

咖啡因對你的睡眠會產生雙重威脅。

It blocks the neurochemical adenosine, which is what tells your brain that you're tired.

神經化學方面，咖啡因會抑制當你疲累時傳訊息給大腦的腺苷。

It releases a cocktail of stimulants into your brain: adrenaline, dopamine, and glutamate.

咖啡因會釋放出混合刺激物給大腦：腎上腺素、多巴胺和穀氨酸。

So, after downing your sixth cup of coffee, you don't just feel awake, but full of energy.

因此六杯咖啡下肚後，你不但會很清醒，還會充滿活力。

It will power you through that two-thirty meeting or the last class of the day.

它能帶你撐過下午兩點半的會議，或熬過最後一節課。

But, if you overdo it, the effect won't wear off when it's time for bed.

可是當你喝太多，咖啡因的效果會到上床時間都還沒消退。

In one study, researchers monitored the sleep of a dozen volunteers.

在一項研究中，研究者監控了12位自願者的睡眠。

Some were given a caffeine pill equivalent to about four cups of coffee and others received a placebo instead.

有些人服下一顆相當於四杯咖啡的咖啡因藥片，其他人則拿到安慰劑。

Even when the volunteers swallowed the caffeine pills six hours before bedtime, they spent significantly less time in the light stages of sleep.

即使自願者在睡前六小時吞下咖啡因藥片，他們的淺眠階段依舊大量減少。

And that can have detrimental effects on daytime function, the authors report.

論文作者指出這會對日間大腦的運作產生負面結果。

It's sort of, like, it's just stuck in this... in this loop, where you're not sleeping 'cause you drink too much coffee.

這就像困在一種循環：你因為喝太多咖啡而睡不好。

And then you wake up in the morning, and you're... you're not well-rested, and then you're drinking more coffee just to stay awake during the day.

隔天早上起來覺得睡不夠，所以你又會喝更多咖啡讓自己保持清醒。

Sound familiar?

你也是這樣嗎？

Here's the good news.

這裡有個好消息。

If you cut yourself off by 2 o'clock, you typically won't have trouble falling asleep.

只要在兩點以後不碰咖啡，你大概就不會有睡眠問題。

That's because the half life of caffeine is around five hours.

因為咖啡因的半衰期大概是五個小時。

And, so, most of its stimulating effects will wear off well before the lights go out.

這樣晚上關燈睡覺前，大部分的刺激效果就會消退。

And if you also limit your consumption, well, then coffee can actually offer a number of health benefits.

如果你有在注意攝取量的話，其實咖啡會帶來不少健康益處。

Research shows that it can help with everything from memory to exercise to your relationships with your colleagues.

研究顯示咖啡對你的記憶、運動、職場關係都有幫助。

And that's great, because for some of us, coffee is something we'll just never give up.

真是太好了，因為對我們來說，咖啡是我們永遠不想放棄的東西！