A walk through the stages of sleep | Sleeping with Science, a TED series

Sleep is perhaps the single most effective thing

翻译人员: Wanting Zhong 校对人员: Chengyu Li

睡眠或许是我们每天都能做的，

that we can do each and every day

可以帮助恢复大脑与身体健康的

to reset the health of our brain and our body.

最有效的一件事。

And by understanding a little bit more about what sleep is,

而通过进一步了解睡眠是什么，

perhaps we can get the chance to improve both the quantity and the quality

我们也许就有机会

改善睡眠的质与量。

of our sleep.

[Sleeping with Science]

[ 科学睡眠 ]

(Music)

（音乐）

So, exactly what is sleep?

那么，睡眠究竟是什么？

Well, sleep, at least in human beings,

至少对人类而言，

is subdivided into two main types.

睡眠可分为两大类型。

On the one hand, we have non-rapid eye movement sleep,

一种是非快速动眼睡眠，

or non-REM sleep for short.

简称“NREM 睡眠”。

But on the other hand,

另一种我们称之为 快速动眼睡眠，

we have rapid eye movement sleep, or REM sleep.

简称“REM 睡眠”。

And non-REM sleep has been further subdivided

NREM 睡眠又可以进一步划分为 [12% 的人的睡眠是纯黑白的 ]

into four separate stages,

四个不同阶段，

unimaginatively called stages one through four,

可以简单地分别命名为 睡眠的第一到第四阶段，

increasing in their depth of sleep.

睡眠深度逐阶段递增。

And as we go into those light stages of non-REM sleep,

当我们进入 NREM 睡眠的 浅睡眠期时，

your heart rate starts to decrease,

我们的心率开始降低，

your body temperature starts to drop

体温开始下降、

and your electrical brain wave activity starts to slow down.

脑电波活动也开始放缓。

But as we move into deeper non-rapid eye movement sleep,

但当我们进入更深的 NREM 睡眠时——

stages three and four,

即第三和第四阶段时，

now all of a sudden the brain erupts

大脑会突然迸发出

with these huge, big, powerful brain waves.

巨大而强劲的脑电波。

The body is actually recharged in terms of its immune system.

身体的免疫系统重新进行蓄能。

We also get this beautiful overhaul of our cardiovascular system.

我们的心血管系统也进行了 完美的修复。

And, in fact, upstairs in the brain,

事实上，在我们的大脑里，

deep non-REM sleep will help consolidate memories

深度 NREM 睡眠 能帮助巩固记忆，

and fixate them into the neural architecture of the brain.

并将记忆锁定在 大脑的神经结构之中。

So that's non-REM sleep.

这就是 NREM 睡眠。

But let's come on to REM sleep,

接下来让我们来讲讲 REM 睡眠，

which is the other main type of sleep.

即睡眠的另一种主要模式。

And it's during REM sleep when we principally have the most vivid,

我们最栩栩如生、光怪陆离的梦境

主要都是在 REM 睡眠期间发生的。

the most hallucinogenic types of dreams.

The brain wave activity actually starts to speed up again.

脑电波活动会重新开始加速。

It's during REM sleep that we receive almost a form of emotional first aid.

在 REM 睡眠中，我们获得的 几乎是一种情绪急救。

And it's also during REM sleep where we get a boost for creativity,

也是在 REM 睡眠中， 我们的创造力获得了提升，

that it stitches information together

通过将信息拼接在一起，

so that we wake up with solutions

我们醒来时就会发现，

之前面临的棘手问题已经 在睡梦中找到解决方案。

to previously difficult problems that we were facing.

Coming back to these two types of sleep,

回到这两类睡眠上来，

it turns out that non-REM and REM will play out

研究结果显示， NREM 睡眠和 REM 睡眠

会彻夜进行大脑支配权的争夺战，

in a battle for brain domination throughout the night,

and that cerebral war is going to be won and lost

而这场争夺战每 90 分钟

every 90 minutes,

就会决出胜负，

and then it's going to be replayed every 90 minutes.

而且每 90 分钟都会 重新上演一次。

And what this produces is a standard cycling architecture of human sleep,

而这就产生了人类睡眠的 标准周期结构——

a standard 90-minute cycle.

标准的 90 分钟睡眠周期。

But what's different, however,

然而不同的是，

is that the ratio of non-REM to REM within those 90-minute cycles

随着夜晚的推进， 这些 90 分钟睡眠周期内的

NREM 睡眠和 REM 睡眠的比例会发生变化。

changes as we move across the night,

such that in the first half the night,

在前半夜，

the majority of those 90-minute cycles

这些 90 分钟睡眠周期大部分

are comprised of lots of deep non-REM sleep,

都是由大量深度 NREM 睡眠构成的，

particularly stages three and four of non-REM sleep.

尤其是 NREM 睡眠的 第三和第四阶段。

But as we push through to the second half of the night,

但当我们进入到后半夜，

now that seesaw balance actually shifts over,

双方的平衡会发生对调，

and instead, most of those 90-minute cycles

因而，此时的 大多数 90 分钟睡眠周期

are comprised of a lot more rapid eye movement sleep, or dream sleep,

是由更多的 REM 睡眠， 即含有梦境的睡眠，

as well as stage-two non-REM sleep,

以及 NREM 睡眠的第二阶段，

that lighter form of non-REM sleep.

即更轻度的 NREM 睡眠构成。

And it turns out that there are implications

事实上，

理解睡眠如何构成是很有意义的。

for understanding how sleep is structured in this way.

Let's take someone who typically goes to bed at 10pm,

比如说一个人 通常在晚上 10 点睡觉、

and they wake up at 6am,

早上 6 点起床，

so they have an eight-hour sleep window.

这样他的睡眠窗口就有八个钟头。

But this morning, they have to wake up early

但是今天早上，他不得不早起，

for an early morning meeting,

为了参加一场清早的会议，

or they want to get a jump start on the day

或者想去健身房，

to get to the gym.

开启新的一天。

And as a consequence, they have to wake up at 4am in the morning,

结果他必须在早上 4 点，

rather than 6am in the morning.

而不是早上 6 点醒来。

How much sleep have they actually lost?

那他实际损失了多少睡眠呢？

Two hours out of an eight-hour night of sleep

一晚八小时睡眠中的两小时，

means that they've lost 25 percent of their sleep.

意味着他损失了 25% 的睡眠。

Well, yes and no.

这样说对，但也不完全对。

They have lost 25 percent of all of their sleep,

他损失了 25% 的整体睡眠，

but because REM sleep comes mostly in the second half of the night

但因为 REM 睡眠 大部分是在后半夜发生的，

and particularly in those last few hours,

尤其是在最后几个小时里，

they may have lost perhaps 50, 60, maybe even 70 percent

所以他有可能损失了 50%、60%，甚至 70% 的

of all of their REM sleep.

REM 睡眠。

So there are real consequences to understanding what sleep is

因此，了解睡眠是什么 以及睡眠的构成

and how sleep is structured.

有着重要的现实意义。

And we'll learn all about the benefits of these different stages of sleep

在接下来的几集里，我们会了解

这些不同阶段睡眠的益处，

and the detriments that happen when we don't get enough of them

以及缺乏睡眠所造成的危害。

in subsequent episodes.