How caffeine and alcohol affect your sleep | Sleeping with Science, a TED series

Many of us like to start the day with a cup of coffee

翻译人员: Judy Huang 校对人员: Wanting Zhong

很多人都喜欢 用一杯咖啡开始一天的生活，

and perhaps end the day with a glass of wine

或许会以一杯葡萄酒 或是别的酒精饮品

or some other kind of alcoholic drink.

结束一天的生活。

But it turns out that these two substances,

但其实这两种物质，

alcohol and caffeine, can have surprising impacts on our sleep.

酒精和咖啡因， 会对我们的睡眠产生惊人的影响。

[Sleeping with Science]

[ 科学睡眠 ]

(Music)

[ 冥想音乐 ]

Let's start with caffeine.

让我们先从咖啡因讲起。

Caffeine is in a class of drugs

咖啡因属于一类我们称为

that we call the psychoactive stimulants.

“中枢神经兴奋剂” 的药物。

And everyone knows that caffeine can make them more alert.

每个人都知道咖啡因 能使他们更加警觉，

It can wake them up.

能让他们更加清醒。

But there are at least two additional,

但是咖啡因至少还有两个

hidden features of caffeine

有些人或许并不知道的

that some people may not be aware of.

隐藏特性。

The first is the duration of action of caffeine.

第一是咖啡因的作用时间。

Caffeine, for the average adult,

对一般的成年人来说，

will have what we call a half-life

咖啡因的 “半衰期”，

of about five to six hours.

大约是五到六个小时。

What that means is that after about five to six hours

这个的意思是， 大约五到六个小时后，

50 percent of that caffeine that you had

你摄入的咖啡因有一半

is still circulating in your system.

还在你的体内循环着。

What that also means is that caffeine has a quarter-life

这也意味着 大约十到十二个小时后

of about 10 to 12 hours.

咖啡因的四分之一 还会留在你的身体里。

In other words, let's say that you have a cup of coffee

换句话说，假如你在下午两点

at 2pm in the evening.

喝了一杯咖啡。

It could be that almost a quarter of that caffeine

可能有近四分之一的咖啡因

is still swilling around in your brain at midnight.

到了半夜还在你的大脑中晃荡。

And as a result, it can make it harder for an individual

结果就是，它会让人更难入睡，

to fall asleep or even stay asleep soundly

甚至难以整晚保持

熟睡状态。

throughout the night.

So that's the first feature of caffeine.

那么这就是咖啡因的第一个特性。

The second issue with caffeine

咖啡因的第二个问题

is that it can change the quality of your sleep.

是它可以改变你的睡眠质量。

Now some people will tell me

这时有些人会告诉我，

that I'm one of those individuals

自己是那种

who can have an espresso with dinner,

能在晚餐时喝一杯浓缩咖啡，

and I fall asleep fine, and I can stay asleep.

之后照样正常入睡， 并睡得很熟的人。

But even if that's true, it turns out

但即便确实如此，

事实上，咖啡因能减少

that caffeine can actually decrease the amount

深度非快速动眼睡眠，

of deep, non-rapid eye movement sleep that we have,

stages three and four of non-REM sleep.

也就是非快速动眼睡眠的 第三和第四阶段。

That's that sort of restorative deep sleep.

这是那种恢复性的深度睡眠。

And as a consequence, you can wake up the next morning,

结果，你在第二天早上醒来，

and you don't feel refreshed,

却并没有感觉精神焕然一新，

you don't feel restored by your sleep.

也不觉得睡眠修复了身体。

But you don't remember waking up,

但你不记得自己中途醒过，

you don't remember struggling to fall asleep,

也不记得入睡困难，

so you don't make the connection,

所以你并没有把咖啡 和睡眠质量联系在一起，

but nevertheless you may then find yourself

不过你可能会发现自己

reaching for two cups of coffee in the morning to wake up

早上需要喝两杯咖啡才能清醒，

rather than one.

而不是一杯。

So that's caffeine, but now let's move on to alcohol,

这就是咖啡因， 不过现在该谈谈酒精了，

because alcohol is perhaps one

因为酒精可能是市面上

of the most misunderstood sleep aids out there.

最被人误解的助眠用品之一。

In fact, it's anything but a sleep aid.

事实上，它根本不是助眠用品。

And it can be problematic for your sleep

而且它在至少三个方面

in at least three different ways.

可能会对你的睡眠造成困扰。

First, alcohol is in a class of drugs

首先，酒精属于一类

that we call the sedatives.

我们叫做 “镇静剂” 的药物。

But sedation is not sleep.

但镇静不是睡眠。

And studies teach us that those two things

研究显示，这两件事

are really quite different.

其实有很大的差异。

Sedation is a case

在镇静的情况下，

where we're simply switching off the firing

我们只是在关停 脑细胞的放电活动，

of the brain cells, particularly in the cortex.

尤其是大脑皮层中的细胞。

And that's not natural sleep.

而这并不是自然睡眠。

In fact, during deep non-rapid eye movement sleep,

事实上，比如说 在深度非快速动眼睡眠时，

for example, the brain has this remarkable coordination

大脑能做出

协调数十万个细胞的壮举，

of hundreds of thousands of cells

that all of a sudden fire together,

让它们突然一起放电，

and then they all go silent,

然后全部沉默，

and then they all fire together, and then they go silent,

然后再次全部一起放电， 再度变得沉默，

producing these big, powerful brainwaves

产生了这些强大的

深度非快速动眼睡眠脑波。

of deep non-REM sleep.

And so that's the first way

那么这就是第一种

in which alcohol can be problematic.

酒精可能引起的问题。

We're mistaking sedation for deep sleep.

我们误以为镇静就是深度睡眠。

The second problem with alcohol

酒精造成的第二种问题是，

is that it can actually fragment your sleep.

它其实可以将你的睡眠碎片化。

Alcohol can actually trigger and activate during sleep

酒精其实能在睡眠中触发并激活

what we call the fight or flight branch

所谓的 “神经系统的

战斗或逃跑分支 ”，

of the nervous system,

which will therefore wake you up more frequently

从而让你整晚

throughout the night.

更频繁地醒来。

And alcohol can even increase the amount

而且酒精甚至能让大脑

of alerting chemicals that are released by the brain,

分泌更多提升警觉的化学物质，

once again fragmenting your sleep.

再次把你的睡眠变得断断续续。

The third and final issue with alcohol and sleep

第三种也是最后一种 关于酒精和睡眠的问题

is that alcohol can actually block

就是酒精其实会阻碍

your rapid eye movement sleep, or your dream sleep.

你的快速动眼睡眠， 或者说是睡梦。

And as we'll learn in subsequent episodes,

我们在之后几集中会学到，

REM sleep, or rapid eye movement sleep, dream sleep,

REM 睡眠，即快速动眼睡眠、 包含梦境的睡眠，

provides a collection of benefits,

能提供一系列好处，

things such as your emotional

比如能改善你的情绪和心理健康，

and mental health, even creativity.

甚至能提升创造力。

Now I'm not here to tell anyone how to live.

我来这里并不是要 教育任何人该如何生活。

I don't want to be puritanical.

我不想过于严格拘谨。

I'm just a scientist.

我只是一名科学家。

What I want to try and do is provide you

我只是想尝试为你提供

with the information about the relationship

关于咖啡因、酒精

between caffeine and alcohol on your sleep

和睡眠关系的信息，

so then you can make an informed choice

这样当你尝试 优先考虑自己的睡眠健康时，

as to how best you want to live your life

就能对你最想过的生活方式

when you're trying to prioritize your sleep health.

做出知情的选择。