平常大家都靠什麼來提神？是咖啡還是午睡？其實，有一種比單獨喝咖啡或小睡一會兒更有效的方法——「咖啡小憩」。
If you're feeling sleepy and need a jolt of energy, there's something you should try.
如果你很瞌睡，需要恢復一些活力，這個辦法你可以試試。
It's more effective than drinking coffee or taking a nap.
比單獨喝咖啡和午後小憩有用。
It's drinking coffee and then taking a nap.
這就是先喝咖啡再小憩一會兒。
It's called a coffee nap.
可稱之為「咖啡小憩」。
It might sound kind of crazy because most people realize that caffeine interferes with sleep.
聽起來有點不靠譜，因為很多人會覺得咖啡因會干擾睡眠。
But it takes a little while for the caffeine to affect you.
但是，咖啡因要經過一段時間後才會起作用。
The caffeine has to go into your small intestine, pass into your bloodstream, and enter your brain, and that takes about 20 minutes.
咖啡因進入你的小腸，進入你的血液，然後進入大腦，需要20分鐘。
If you spend those 20 minutes unconscious, you're going to wake up feeling pretty great.
如果這時睡20分鐘，醒來後會覺得相當精神。
To understand why, it helps to know what's making you groggy in the first place.
要了解其中原因，首先要明白到底是什麼原因讓你昏昏沉沉的。
So there's a molecule inside your brain called adenosine and it plugs into little receptors inside your brain and makes you feel tired.
大腦中有一個分子物叫做腺嘌呤核苷，這個物質會和大腦裡的受體結合，讓人困意綿綿。
Adenosine is a byproduct of brain activity, so it builds up throughout the day and starts to slow down your neurons.
腺嘌呤核苷是你大腦活動的副產物，經過一整天累積，然後會使你的神經活動放緩。
Caffeine chemically looks a whole lot like adenosine.
咖啡因和腺嘌呤核苷結構相似。
And when you ingest caffeine and it enters your brain, it blocks adenosine from fitting into those receptors.
咖啡因經吸收後進入大腦，會阻止腺嘌呤核苷與這些受體結合。
A lot of people have said that this like taking a car and putting a block of wood under the brake pedals.
很多人覺得這就像是開車時，腳剎擋了一塊木板。
Caffeine keeps your brain from slowing itself down.
咖啡因讓大腦保持活力。
The great thing about coffee naps is that sleep naturally clears out adenosine from the brain.
咖啡小憩的妙處在於，可以通過睡眠將大腦裡的腺嘌呤核苷自然清除。
So the caffeine doesn't even need to compete with the adenosine to fit into those receptors.
所以咖啡因不用和腺嘌呤核苷競爭受體。
So what's the evidence that this really works?
有什麼證據證明這個過程有效？
There's not a huge body of work but there are some studies.
這不是什麼大工程，但的確有一些研究。
When people took a 15-minute coffee nap, they went on to commit fewer errors in a driving simulator than when they only drank coffee or only took a nap.
當有人咖啡小憩15分鐘，他們在駕駛模擬器上出錯更少，比僅僅喝杯咖啡或者小憩更有用。
As the test subjects were doing this really boring hour-long drive simulation, they were asked every 3 minutes to report their sleepiness level.
測試對象接受了這個無聊且長時間的駕駛模擬測試，每隔3分鐘就要報告自己的瞌睡等級。
And the coffee nap group was consistently more alert.
僅喝咖啡的那一組不斷發出預警信號。
Meanwhile a Japanese study found that people who took a caffeine nap performed a lot better on a series of memory tests.
其後一項日本研究發現，咖啡小憩後，人們在一系列記憶測試中的成績將大幅度提升。
The challenge of the coffee nap is to time it just right.
咖啡小憩的難點在於時機是否正確。
You want to drink it quickly, so it maybe you could do espresso shots or iced coffee if that makes it easier.
你想快速喝完一杯咖啡，如果想易於完成，可能就得喝一杯濃縮咖啡或者冰咖啡。
And then set an alarm before you fall asleep to wake up before 20 minutes because if you nap too long you're much more likely to enter deeper stages of sleep, and you'll have what scientists call sleep inertia, which is basically grogginess.
睡前再定一下鬧鐘，20分鐘後醒來。如果睡的時間太長就會進入深度睡眠，就是科學上說的睡眠慣性，會讓人感覺昏昏沉沉的。
If you have trouble falling asleep that quickly, the studies found that you can still benefit from the coffee nap.
如果難以很快入睡，研究證明，咖啡小憩還是可以讓你重現活力的。
Even just drinking the caffeine and getting a few minutes of restful half-sleep is going to make you feel more alert when you do get up 20 minutes later.
即便僅喝一杯咖啡，然後安靜地閉目養神，保持半睡眠狀態，也會讓你在20分鐘後，精神更好。