第13讲 并不平静—睡眠在线视频

我们的意识每天都会发生一些变化
Our consciousness will change every day

到了晚上 我们就会进入睡眠状态
At night, we will go to sleep

在古代 人们对睡眠的理解很少
In ancient times, people had little understanding of sleep

很多人认为睡眠与死亡很相似
Many people thought that sleep was very similar to death

因为他们认为
because they thought that

睡眠的时候人的灵魂会暂时离开人的身体
the soul left the body temporarily during sleep

1937年 科学家研究睡眠的方法终于取得了突破
In 1937, scientists finally made a breakthrough in the study of sleep

开始使用脑电图技术
and began to use EEG technology

来记录睡眠过程中的脑电波的活动
to record the brain wave activities during sleep

在睡眠研究中
In sleep research

研究人员通常把电极放在志愿者的头上
researchers usually put electrodes on the heads of volunteers

记录他们脑电的变化
to record the changes of EEG

以及他们身体的各种功能指标的变化
and various functional indicators of their bodies

如呼吸 肌肉力量 心率 血压等
such as respiration, muscle strength, heart rate, blood pressure, etc

通过分析这些指标的变化
By analyzing the changes of these indicators

科学家发现
scientists found that

在整个睡眠过程中
during the whole sleep process

人的脑电图都表现出系统的
people's EEG showed systematic

并且可以预测的变化
and predictable changes

总的来说 睡眠表现出若干周期
In general, there were several cycles in sleep

每个周期都会出现快速眼动睡眠和非快速眼动睡眠
each of which is characterized by REM sleep and non REM sleep

研究发现
The studies find that

当大脑清醒和警觉的时候
when the brain is awake and alert

脑电图中会出现许多β波
there are many β waves in EEG

β波是一种频率较高 波幅较小的波
β wave is a wave with high frequency and small amplitude

每秒有14-30个周期
which has 14-30 cycles per second

当准备睡觉的时候
When we are ready to go to sleep

大脑处于安静状态
our brain are in a quiet state

β波会被a波所替代
and β wave is replaced by α wave

a波的频率比较低
The frequency of α wave is relatively low

每秒有8-13个周期
8-13 cycles per second

波幅稍微大一点
and the amplitude is slightly larger

进入睡眠以后
After going to sleep

脑电图以δ波为主
the EEG is dominated by δ wave

δ波频率更低 波幅更大
with lower frequency and larger amplitude

进入睡眠以后
At the beginning of sleep

会首先进入非快速眼动睡眠
non-rapid eye movement sleep begins

这种睡眠分成四个阶段
This kind of sleep is divided into four stages

第一阶段
In the first stage

脑电频率约为每秒3-4个周期
the EEG frequency is about 3-4 cycles per second

处于轻度睡眠的状态 身体很放松
and its a light sleep state, with the body very relaxed

呼吸会减慢
breathing slowed down

但很容易被外部刺激唤醒
but it is easy to be awakened by external stimulus

第二阶段的脑电频率
The frequency of EEG in the second stage

跟第一阶段相似
is similar to that in the first stage

但是偶尔会出现一个高频 高波幅的脑电波
but occasionally there is a high-frequency, high amplitude EEG

这种脑电波被称做睡眠锭
which is called sleep spindle

这时候个体很难被唤醒
At this time, it is difficult for individuals to be awakened

第三个阶段
In the third stage

脑电波的频率会继续降低
the frequency of brain waves will continue to decrease

每秒1-2个周期
and there are 1-2 cycles per second

大部分脑电波开始显示δ波时
When most brain waves begin to show delta waves

表明个体已经进入了睡眠的第四阶段
it indicates that individuals have entered the fourth stage of sleep

也就是深度睡眠阶段
that is, deep sleep stage

在这个阶段 肌肉会逐步放松
In this stage, muscles will gradually relax

身体机能的各种指标会减缓
various indicators of body function will slow down

有时会发生梦呓 梦游 尿床等等
the sleepers will turn over and are easy to be awakened

第三和第四阶段的睡眠
The third and fourth stages of sleep

通常被称为慢波睡眠（SWS）
are commonly referred to as slow wave sleep (SWS)

几乎每个人都会经历这四个睡眠阶段
Almost everyone goes through these four sleep stages

非快速眼动睡眠的四个阶段大约持续90分钟
The four stages of non REM sleep last about 90 minutes

这个周期结束后
At the end of this cycle

睡眠者会翻身 很容易被叫醒
the sleepers will turn over and easily wake up

然后突然进入一个新的阶段
then suddenly enter a new stage

叫做快速眼动睡眠（REM）阶段
called rapid eye movement sleep stage

这一阶段出现了高频率 低波幅的脑电波
In this stage, there are high frequency and low amplitude brain waves

这与清醒状态下的脑电波非常相似
which are very similar to those in awake state

心律和血压变得不规则
The heart rate and blood pressure become irregular

呼吸也变得迅速 就像清醒或恐惧一样
breathing becomes rapid, just like they are awake or fear

而肌肉依然是松软的
while the muscles are still soft

这时候
At this time

睡眠者的眼球开始快速地上下左右移动
the eyes of sleepers begin to move up, down, left and right quickly

常常会伴随栩栩如生的梦
often accompanied by vivid dreams

如果在这一阶段把睡眠者唤醒
If the sleepers are awakened at this stage

他们通常会报告正在做梦
they usually report that they are dreaming

2007年 美国睡眠医学学会
In 2007, the American Academy of Sleep Medicine

将第三阶段和第四阶段合并为一个阶段
combined the third and fourth stages into one stage

即第三阶段或深度睡眠阶段
namely the third stage or deep sleep stage

所以 睡眠周期通常
Therefore, the sleep cycle usually consists of

由非快速眼动睡眠的三个或四个阶段
three or four stages of non REM sleep

再加上快速眼动睡眠阶段组成
plus REM sleep stage

每个周期通常持续90-100分钟
Each cycle usually lasts for 90-100 minutes

整夜睡眠大约有4-6个这样的周期
and the whole night sleep has about 4-6 such cycles

在每个晚上的睡眠周期
In each night's sleep cycle

第一次快速眼动睡眠持续约10分钟
the first REM sleep lasts about 10 minutes

最后一次持续约1个小时
and the last REM sleep lasts about 1 hour

刚出生的婴儿每天睡眠16个小时
Newborn babies sleep 16 hours a day

快速眼动睡眠大概占一半
and REM sleep accounts for about half of them

年轻人每天睡7-8个小时
young people sleep 7-8 hours a day

其中 快速眼动睡眠大概有2.5个小时
of which REM sleep is about 2.5 hours

到了50岁 每天只睡6个小时
by the age of 50, people only sleep 6 hours a day

快速眼动睡眠只有20分钟
and REM sleep is only 20 minutes

睡眠有什么用呢
What's the function of sleep?

人和动物一样都要依次经历各个睡眠阶段
People and animals have to go through different stages of sleep in turn

这表明睡眠是进化的结果
which shows that sleep is the result of evolution

是具有适应意义的
and has adaptive significance

科学家认为
Scientists believe that

睡眠模式反映了两个功能之间的平衡
sleep patterns reflect the balance between two functions

第一个功能是保存能量
The first function is to conserve energy

这是非快速眼动睡眠的一个功能
which is a function of non REM sleep

也就是说
That is to say

在动物不需要觅食和寻找配偶的时候
when animals don't need to look for food and mates

睡眠可以节省一定的能量
sleep can save some energy

第二个功能是保持警觉
The second function is to be alert

能量必须保存 因此必须睡眠
Energy must be conserved, so we must sleep

但睡眠时警觉性会降低
but when we sleep, our alertness will be reduced

怎么保持警觉呢
How can we keep alert?

睡眠阶段的周期性变化
The periodic changes of sleep stage

能使动物的警觉性虽然有所降低
can reduce the alertness of animals

但也能使被攻击的风险降到最低
but also minimize the risk of being attacked

睡眠还有第三个功能
Sleep also has a third function

就是大脑修复
which is brain repair

在非快速眼动睡眠阶段
During non REM sleep

大脑组织的损伤能得到修复
brain tissue damage can be repaired

那么快速眼动睡眠对认知活动非常重要
REM sleep is very important for cognitive activity

深度睡眠和快速眼动睡眠如果被剥夺
If deep sleep and rapid eye movement sleep are deprived

会严重影响认知表现
cognitive performance will be seriously affected

出现注意困难和工作记忆困难
attention and working memory difficulties will occur

也会损伤运动技能
and motor skills will also be damaged

研究发现
One study find that

睡眠剥夺后的的司机
drivers with sleep deprivation

发生交通事故的概率高很多
are much more likely to have traffic accidents

很多严重的工业事故是因为个人睡眠不足导致的
and many serious industrial accidents are caused by lack of sleep

在现代社会中
In modern society

学生睡眠已经成为一个社会问题
students' sleep has become a social problem

学生的睡眠不足导致学习效率下降
Students' lack of sleep leads to the decline of learning efficiency

另外 如果你每天都睡的很好
In addition, if you sleep well every day

那么恭喜你
congratulations

因为人群中大约只有四分之一的人
because only about a quarter of the people

像你睡得这么好
sleep as well as you

有些人入睡难的问题很有规律
Some people have trouble sleeping regularly

并对正常生活有不良影响 这就是失眠症
and have bad effects on their normal life, which is insomnia

失眠往往伴随精神失调
Insomnia is often accompanied by mental disorders

如焦虑 精神抑郁等等
such as anxiety, depression and so on

失眠在心理正常和反常的情况下都有可能发生
Insomnia can occur under normal and abnormal mental conditions

多数情况下
In most cases

压力消除了 正常的睡眠就能恢复
if the pressure is eliminated, normal sleep can be restored

如果担心失眠 就会加重失眠
Worry about insomnia will aggravate it

好 今天的课就讲完了
OK, that’s all for today

现在回顾一下主要内容
Now let's review the main content

今天我们主要讲了睡眠的阶段
Today we mainly talked about the stage of sleep

科学家把睡眠分为
Scientists divide sleep into

非快速眼动睡眠和快速眼动睡眠
non-rapid eye movement sleep and rapid eye movement sleep

其中非快速眼动睡眠又包括三个或四个阶段
and REM sleep includes three or four stages

睡眠有保存能量
Sleep have the functions of conserving energy

保持警觉和大脑修复的功能
keeping alert and repairing the brain

如果睡眠被剥夺
If sleep is deprived

会产生广泛的负面影响
there will be a wide range of negative effects

另外
In addition

我们在附加学习材料中还准备了
we have prepared other knowledge

生物节律的其他知识
of biological rhythm in additional learning materials

大家可以去学习
which you can learn

下次课我们会介绍其他几种意识状态
Next time, we will talk about several other states of consciousness

分别是梦 催眠和冥想
namely, dream, hypnosis and meditation

好 下次再见
OK, see you next time