揭秘：当你睡觉时你的身体在做什么

我们一生当中的三分之一都是在睡眠中度过的。睡眠如此重要，但是我们对睡眠却知之甚少，就连科学家也无法完全破解睡眠密码。当你睡觉的时候，你大概不知道，你的身体依旧忙碌得很呢！那么，你睡着之后身体都在忙些啥呢？

1. KEEPING TIME 生物钟仍在运行

You might be asleep but your hypothalamus is not. It's carefully keeping time for you as part of your circadian rhythm. This not only helps you feel tired so that you go to sleep with the release of melatonin, but a protein called PER is released in the morning that gradually wakes you up, often right before your alarm clock is set to go off.

你也许睡着了，但你的下丘脑没有睡。它还在一丝不苟地运行着生物钟。下丘脑会分泌褪黑激素，让你感到困倦，到了早晨，则会释放一种名为PER的蛋白质，让你逐渐苏醒，通常会在闹钟快响的时候把你叫醒。

2. SPOUTING OFF 说梦话

What do you have to say when you're asleep? Sleep-talking or somniloquy can range from random noises to complete sentences. About 5 percent of adults do it (it's slightly more common in children), and it can happen during any stage of sleep. It's most common in men and kids, and can be brought on by fever, sleep deprivation, stress, anxiety, or depression. Don't worry though—there's no evidence people tell their deepest, darkest secrets while asleep. The biggest concern may be that you're keeping your sleep partner awake.

当你沉睡的时候你会说什么呢？梦话可能是语焉不详的呢喃，也可能是完整的句子。大约5%的成年人会说梦话（小孩说梦话更常见一点），而且在睡眠的任何阶段都可能说梦话。男人和孩子说梦话最多见，可能是由发烧、缺觉、压力、焦虑或抑郁引起。不过不要担心——没有证据表明人们会在睡梦中说出自己藏得最深、最阴暗的秘密。最令人烦恼的恐怕是说梦话会把一起睡觉的人吵醒。

3. GRINDING YOUR TEETH 磨牙

Most people grind their teeth while they are asleep, at least sometimes. This habit, called bruxism, can be caused by emotional or psychological states like stress or anxiety, from an abnormal bite (misalignment of your teeth), or even from sleep apnea. Most people are unaware they do this until their dentist notices evidence of unusual wear. If you're damaging your teeth at night, your dentist can give you a mouth guard to prevent it.

多数人在睡觉的时候都会磨牙，至少总有那么几次。这种磨牙症可能是由压力或焦虑等情感或心理状态引发的，也可能是由牙齿不齐导致的，甚至可能和睡眠呼吸暂停有关。在牙医发现不寻常的磨损痕迹之前，多数人都没有意识到自己磨牙。如果你睡觉的时候磨牙，牙医可以给你一个口腔防护器来预防损伤。

4. CLEARING YOUR BRAIN 清理大脑垃圾

You think you're resting, but your brain is doing some serious housekeeping every single night. While you are asleep your brain clears out some memories and cements and reorganizes others. The brain also physically cleans itself with a flood of cerebrospinal fluid, which removes unnecessary proteins that can act as toxins.

你以为你在休息，但你的大脑每天夜里都在认真地管理“家务”。在你睡觉的时候，你的大脑会清理掉一些记忆，巩固和整理其他一些记忆。大脑还会用脑脊液自我清洁，去除不必要的有毒蛋白质。

5. GETTING PARALYZED 四肢麻痹

Your muscles are frozen for part of every night. It's actually normal and healthy to be paralyzed during sleep. During rapid eye movement (REM) sleep your brain is busy dreaming, but to protect yourself from responding to the dreams (for example, screaming when something scary happens or waving your arms to push away an oncoming danger in your dream), your body's muscles are paralyzed. It's possible to actually wake up during the tail end of this cycle and be awake but unable to move, which can be upsetting or even terrifying. It's also relatively common, having occurred to about 40 percent of people. These episodes usually pass quickly.

你的肌肉每天晚上都有一段时间会处于麻痹状态。在睡眠中感到麻痹是正常也是健康的。在快速眼动睡眠期间，你的大脑正忙着做梦，但为了保护自己不对梦中情景做出反应（比如在梦中发生可怕的事情时尖叫，或者挥舞你的手臂赶走梦中即将到来的危险），身体的肌肉会处于麻痹状态。在梦境临近结束时醒来，你可能会无法动弹，这可能会让你困扰甚至惊恐。这也是相对常见的，约有40%的人发生过这种情况。这种麻痹状态通常很快会过去。

6. DROPPING POUNDS 减肥

You might be conked out at night, but it turns out your body is still working hard. Each night you lose about a pound due to the water vapor you expel while breathing. You also lose weight since you're expelling carbon atoms with each exhalation. Because of this, the best number on your scale will be first thing in the morning, so take advantage of it!

你可能在晚上就停摆了，但是你的身体却依然在努力工作。每天晚上，你呼出的水蒸气都会让你减重约1磅（约等于454克）。你在每次呼气时都会排出碳原子，这也会让你减重。正因如此，早上刚起床就称体重，会得到最满意的结果，所以要把握这个机会哦。