suddenly feels like you're falling in your whole body twitches what is that

你突然因為全身抽蓄而感覺身體在下墜，那是什麼？

well that's a jerk, a hypnic jerk to be precise, a hypnic jerk sometimes called a sleep start is

那是抽動，準確地來說是『入睡抽動』，入睡抽動有時也被稱為 『Sleep Start』是

the scientific term for what happens when you jump in your sleep there the

一個科學名詞用於解釋當你在入睡抽動時，你的

involuntary muscle twitches that happened in your arms legs or even your

不隨意肌抽動將發生在你的手和腳上，或甚至是

entire body as you drift off to dreamland, most people get them roughly

你的全身，當你慢慢步入夢鄉的時候，大部分人都會這樣，大約

70% of the population jumps in their sleep, but why do they happen

70% 的人都會發生入睡抽動，但為什麼發生這種現象呢？

there are two main theories based on neural science and evolution most common

這裡有基於神經科學及進化論的兩個理論，最常見的

explanation is that as you fall asleep there are two different systems your

解釋是當你入睡後，有兩個不同的系統在你的

brain that are basically battling each other. System number one, a network of

腦中互相競爭。第一個系統，一個網絡由

nerve cells called the reticular activating system is just below your

神經細胞組成並成為網狀活化系統，正好落在你

cerebral cortex the big wrinkly part of your brain. when this system is in full

大腦皮層的下方，就在腦部最多皺著的地方。當這一個系統全力運作時

force you feel alert, it essentially helps keep you awake. system number two

你會感到警惕，這實質上會讓你感到精神。第二個系統

call the ventrolateral preoptic nucleus or VLP0 for short is located near the

稱做為腦側室前視核或者簡稱『VLP0』則落在於

optic nerve and influences your sleep cycle, the VLP0 sometimes referred

視神經附近並且會影響你的睡眠週期，『VLP0』有時也被稱為

to as the sleeps switch, as you fall asleep each night or during nap time

『Sleep Switch』，當你入睡或者是午休時

the VLP0 system begins to take control from the reticular activating

VLP0 系統將會開始控制你的網狀活化系統

system during this hand off from one system to another the alert part of your

在這個系統的交接過程中，腦部中的警惕系統

brain can still sometimes stimulate your muscles causing twitches, these hypnic jerks are

有時候還會刺激你的肌肉並造成抽動，這些入睡抽動

last-ditch attempts by the reticular activating system to maintain control of

是網狀活化系統最後一搏在於嘗試控制

your body as you more or less choose to sleep, system number one usually

你的身體，當你比較偏向於不睡覺時，第一個系統一般會

seized control the system number two the VLP0 and the hypnic jerks eventually

取得控制第二個系統『VLP0』，然後入睡抽動將終於

stopped, so these jerks are thought to be the result of a sleeping waking war

停止，所以這些抽動也被認為是一個「睡覺」或「清醒」之間的戰爭，

happening in your body each time you try to get some shut-eye, another less common

發生在你的身體中每當你想要休息，另一個比較不普遍的

theory for what causes hypnic jerks involve our primate ancestors. some scientists think

理論用於解釋這個抽動是由於我們靈長類動物的祖先，一些科學家認為

that the ancient primate brain associated relaxation or the beginning

古時候的靈長類腦是和『放鬆』有關聯或在剛開始

stages of sleep with falling out of a tree, hypnic jerks were a way of waking the

階段入睡時跌下樹時，入睡抽動是一個快速喚醒

primate up quickly so they could take action and possibly break their fall.

靈長類的方法，以致他們可以採取行動避免下跌。

so these muscular twitches might have stayed with us as we evolved over the years.

所以這些肌肉抽動也許就這樣隨著我們演變而保留下來了

whatever causes hypnic jerks they're nothing to worry about according

無論是什麼造成入睡抽動，這沒有什麼好擔心的，根據

to most experts but if you don't love getting jolted awake feeling like you're

大部分專家說法，但如果你不喜歡被震醒，感到你好像

plummeting near-death there are some steps you can take to limit how many

快要跌至死亡，這有些方法你可以用於限制

sleep start to experience things like high caffeine consumption, working out in the evening hours,

『Sleep Start』的發生，就好比如攝取大量的咖啡因，在傍晚時鍛煉

high stress levels and lack of sleep can cause more frequent

擁有很大的壓力或者缺乏睡眠可會造成更頻繁

and more intense hypnic jerks, so cutting back on the coffee, getting your workout

或是更嚴重的入睡抽動，所以減少咖啡的攝取，鍛煉時段在

done in the morning and managing your stress levels and sleeping patterns

早上完成並且管理你的壓力和睡眠習慣

might result in fewer hypnic jerks, but like I said they're not dangerous

可能會減少入睡抽動，但就如我剛說的這些抽動並不危險

so if they don't bother you, no need to ditch your afternoon latte, there're bigger jerks

所以如果他們並不會讓你困惑，你不需要減少你中午的拿鐵，還有更多其它的「混蛋」

out there to battle after all. Thanks to all of our patrons on patreon for not being jerks

在需要去抗爭。感謝所有在 Patreon 的支持者並不是「混蛋」

you keep these answers coming you'd like to submit a question to be

你們保持這些答案的到來，如果你們想要提出任何問題

answered or get some videos a few days before everyone else, just go to

讓我們回答，或是比其他人早幾天收到一些影片，只要到

patreon.com/scishow and don't forget to go to youtube.com/scishow

patreon.com/scishow 並且不要忘記到 youtube.com/scishow

and subscribes.

並且訂閱。