介绍

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🌐 原视频链接： Anna Rothschild: What staying up all night does to your brain | TED Talk

📜 原作者： Anna Rothschild

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字幕制作：Gearless Joe

备考情境

你只差一场罗马帝国史的期末考试，就能迎来轻松的春假。可眼下，你还有一大堆内容要复习。于是，你决定像很多过来人一样，“通宵”拼一把。

当你整夜不睡， 就相当于在与自己身体的自然昼夜节律作对。昼夜节律指的是所有生物在二十四小时内经历的各种信号变化，比如睡觉和清醒，并且这些变化深受光线的影响。

不过现在，你还算精神，继续奋战在“凯撒时代”的复习里。

睡眠原理与脑内化学

当太阳落山时，你的眼睛会把光线变暗的信号发送给大脑中名为“视交叉上核”的区域。这块区域基本上就是你的“生物钟”。它会通知松果体开始分泌褪黑激素，褪黑激素能帮助身体做好睡眠准备，通常会在你平时入睡前约两小时开始增加。

同时，丘脑下部和脑干的神经元会释放一种叫做GABA的化合物，它能减缓大脑活动，并产生镇静效果。

这时，你也逐渐接近自己的正常就寝时间。由于大脑在入睡前需要降温，你的体温也开始下降。

看看那张地图……好像是一张脸？呃……也许吧。你注意力开始飘忽。

其实，白天你的大脑一直在释放一种叫“腺苷”的废物。腺苷与大脑受体结合得越多，你就越疲惫、越难集中注意力。

来杯咖啡吧。

咖啡因能阻断腺苷与受体结合，给你带来短暂的能量提振，但同时也可能让你紧张不安，焦虑加剧。

记忆与熬夜表现

现在，你正顺利地刷着抽认卡；那些人名、时间，都暂时存进“海马体”了。

一般来说，睡觉时，这些信息会得到巩固，并被转移到大脑新皮层作为长期记忆。

好在你只需要记住它们到明天就行。

但如果你持续缺觉，就可能出现“微睡眠”——只持续几秒钟的短暂瞌睡，且毫无征兆。

为了保持清醒，你伸了个懒腰，可此时你的运动技能已经大打折扣了。

有研究发现，清醒了19小时以上的人，在协调能力和反应速度上，跟喝过酒的人差不多。

天渐渐亮了。随着太阳升起，你的松果体也停止分泌褪黑激素。这会让你产生“第二波”活力。尽管你刚刚熬了一夜，却似乎还能保持好心情地去上学。

不过，睡眠不足也会带来短暂的欣快感，这是因为多巴胺水平短时间内被推高，但不幸的是，它也可能让你更容易做出不明智的决定。

考试开始时，你感觉还不错，前面是选择题；直到你看到简答题的那一刻……

研究认为，人在睡眠中，大脑会整理白天的各种想法，并将新旧记忆互相关联。

所以，虽然你还能机械地记起一些事实，但要再深入分析或解决问题就非常吃力了。

熬夜的后果与长期影响

看着空白试卷，你彻底无计可施。

焦躁、烦闷地回到房间——大脑里处理情绪的“杏仁核”彻底失控，而平时负责约束它的前额叶皮层还没恢复过来。

此刻，你只想好好躺在床上。

熬一晚还好，身体和大脑往往能较快反弹，毕竟我们无法每次都控制好睡眠时长。

但若长期睡眠不足，或者频繁打乱作息，你的身体会吃不消。

经常每晚少于七小时的睡眠，会引发从糖尿病、中风到慢性疼痛等各种健康隐患，也让你更容易出现诸如抑郁等心理问题。

睡眠习惯甚至能影响学习成绩——有研究指出，作息规律的大学生平均GPA更高。

因此，下次想要熬夜时，记住：罗马不是一天建成的，更何况是一晚上？

You're just one Roman Empire history final away from a relaxing spring break. But you still have so much to study! So you decide to follow in the footsteps of many students before you and pull an all-nighter.

When you stay up all night, you're fighting against your body's natural circadian rhythms. These are the cyclical changes that virtually all living things experience over the course of a 24-hour period—such as sleeping and waking—and they're heavily influenced by light. But for the moment, you're alert and powering through the rule of Julius Caesar.

As the sun sets, your eyes send signals about the dwindling light to a part of your brain called the suprachiasmatic nucleus. This is basically your circadian rhythm's clock. It alerts your pineal gland to start producing melatonin. That's the hormone that helps prepare your body for sleep, and levels start to rise about two hours before your normal bedtime. At the same time, neurons in the hypothalamus and brain stem release a compound called GABA. This slows down activity in your brain and can have a calming effect.

You're approaching your normal bedtime. Since the brain needs to cool down before sleep, your core body temperature starts to drop.

Huh, that map kind of looks like a face. Uh-oh, your attention has started to drift. Throughout the day, your brain has been releasing a waste product called adenosine. The more adenosine latching onto receptors in your brain, the more tired and inattentive you become. Time for a cup of coffee. Caffeine blocks adenosine from binding to receptors, which can give you a boost of energy. However, it might also make you jittery and increase your anxiety.

You're acing these flashcards! Right now these dates and names are being stored in an area of the brain called the hippocampus. Normally when you go to sleep, memories like these are consolidated and slotted into long-term storage in your brain's neocortex. So it's a good thing you only need to remember this information through tomorrow.

Microsleeps are unpredictable periods of sleep that last for only a few seconds and are triggered by sleep deprivation. You stretch in an attempt to stay awake. But at this point, your motor skills have also taken a hit. Studies have found that people who have been awake for 19 hours have similar coordination and reaction times as those who have been drinking.

As the sun rises, your pineal gland stops releasing melatonin. You feel a “second wind” come on. And despite everything, you leave for school in a really good mood. Sleep deprivation can briefly induce euphoria. It's caused by a temporary boost in dopamine levels, which can unfortunately also lead to poor choices.

The final starts off well. It's all multiple choice! But then you get to the essay portion. It's thought that during sleep, our brains process ideas and draw connections between new memories and old ones. So your sleepless brain might be able to regurgitate facts, but you're finding it more difficult to find patterns or problem solve. You stare at the blank page, defeated.

You head up to your room, anxious and irritable. Your amygdala, the part of the brain involved with processing emotion, is going haywire. Your prefrontal cortex usually keeps your amygdala in check, but it still isn't firing on all cylinders. Your bed has never felt so sweet.

After one sleepless night, your body and brain bounce back pretty quickly. Which is a good thing since we can't always control how much sleep we get. But going for long periods without a good night's sleep or constantly changing your bedtime can take its toll. Regularly getting less than seven hours of sleep each night is linked to all sorts of health issues, from diabetes to stroke to chronic pain. It also leaves you more vulnerable to developing mental health issues like depression.

Your sleep schedule can even affect your grades. Studies have shown that college students who keep regular sleep hours have, on average, a higher GPA than students who don't. So the next time you're thinking of pulling an all-nighter, remember that Rome wasn't built in a day, or for that matter, one night.