On the second day, his eyes stopped focusing.

在第二天，他雙眼已無法對焦。

Next, he lost the ability to identify objects by touch.

接著，他喪失了透過觸覺辨認物體的能力。

By day 3, Gardner was moody and uncoordinated.

到了第三天，Gardner 變得暴躁易怒而且肢體不協調。

At the end of the experiment, he was struggling to concentrate, had trouble with short-term memory, became paranoid, and started hallucinating.

在實驗的最後，他難以保持專注、短期記憶失常、變得偏執，而且還出現幻覺 。

Although Gardner recovered without long-term psychological or physical damage,

雖然後來 Gardner 已完全恢復，且無長期心理或生理的後遺症，

for others, losing shuteye can result in hormonal imbalance, illness, and, in extreme cases, death.

對其他人而言，喪失睡眠可能導致賀爾蒙失調、疾病，在極端的例子中甚至可能致死。

We're only beginning to understand why we sleep to begin with, but we do know it's essential.

我們對於「人類為何需要睡眠」的理解還在粗淺階段，但目前已確定睡眠是必要的。

Adults need 7 to 8 hours of sleep a night and adolescents need about 10.

一般成人晚上需要 7 到 8 小時的睡眠，青少年則需要約 10 小時。

We grow sleepy due to signals from our body telling our brain we are tired, and signals from the environment telling us it's dark outside.

當我們的身體發出各種訊號告訴大腦我們累了時，睡意便會開始湧現另外，環境發出像是天色暗了的訊號也有影響 。

The rise in sleep-inducing chemicals, like adenosine and melatonin, send us into a light doze that grows deeper, making our breathing and heart rate slow down and our muscles relax.

隨著睡意漸增，腺苷和褪黑素的分泌也隨之增加使，我們進入淺眠後逐漸熟睡，並使得呼吸和心跳速率趨緩、肌肉放鬆。

This non-REM sleep is when DNA is repaired and our bodies replenish themselves for the day ahead.

當進入上述非 REM 睡眠周期時，身體會重新恢復活力，DNA 也於此時得到修補，彌補一整天的疲憊。

In the United States, it's estimated that 30% of adults and 66% of adolescents are regularly sleep-deprived.

在美國，據估計有 30% 的成人和 66% 的青少年長期睡眠不足。

This isn't just a minor inconvenience⏤staying awake can cause serious bodily harm.

這不是一個小問題，熬夜可能會造成嚴重的健康問。

When we lose sleep, learning, memory, mood, and reaction time are affected.

當我們缺乏睡眠，學習、記憶、心情以及反應速度都會受到影響。

Sleeplessness may also cause inflammation, hallucinations, high blood pressure, and it's even been linked to diabetes and obesity.

缺乏睡眠還會引起發炎、幻覺、高血壓甚至還與糖尿病、肥胖等有關聯 。

In 2014, a devoted soccer fan died after staying awake for 48 hours to watch the World Cup.

在 2014 年，一名瘋狂的足球粉絲因為連續熬夜 48 小時看世界盃而猝死。

While his untimely death was due to a stroke, studies show that chronically sleeping fewer than 6 hours a night increases stroke risk by 4 and a half times compared to those getting a consistent 7 to 8 hours of shuteye.

雖然他過早的死亡是中風導致，但據研究顯示若長期的睡眠少於六小時，中風的風險比睡滿 7 到 8 小時的人多 4.5 倍。

For a handful of people on the planet who carry a rare inherited genetic mutation, sleeplessness is a daily reality.

對於地球上部分遺傳到稀有地基因突變的人而言，失眠對他們來說是家常便飯。

This condition, known as Fatal Familial Insomnia, places the body in a night mirror state of wakefulness, forbidding it from entering the sanctuary of sleep.

該病症被稱為「致死性家族失眠症」，患者的身體會徹夜保持清醒無法進入夢鄉。

Within months or years, this progressively worsening condition leads to dementia and death.

在數個月或者數年後，逐漸惡化的病症會導致失智或者死亡。

How can sleep deprivation cause such immense suffering?

區區睡眠剝奪怎會引起如此大的危害呢？

Scientists think the answer lies with the accumulation of waste products in the brain.

學者們認為答案應該就在腦中不斷累積的代謝廢物上。

During our waking hours, our cells are busy using up our day's energy sources, which get broken down into various byproducts, including adenosine.

在我們醒著的時候，體內的細胞忙著將每日獲取的能量來源分解成各種副產品，包括腺苷。

As adenosine builds up, it increases the urge to sleep, also known as sleep pressure.

當腺苷逐漸累積，人便會感到困倦該作用被稱為「睡眠壓力」 。

In fact, caffeine works by blocking adenosine's receptor pathways.

事實上，咖啡因的作用正是卡住腺苷的受器（咖啡因與腺苷分子相似）。

Other waste products also build up in the brain, and if they're not cleared away, they collectively overload the brain and are thought to lead to the many negative symptoms of sleep deprivation.

其餘各種代謝物質也會在腦中累積，如果這些物質不被清除掉，就會使得腦部負擔過重，學者認為睡眠剝奪導致的許多病症正是因此而生。

So, what's happening in our brain when we sleep to prevent this?

那麼，我們正常的腦袋在睡眠時是如何避免上述作用發生呢？

Scientists found something called the glymphatic system, a clean-up mechanism that removes this build-up and is much more active when we're asleep.

科學家們發現一種稱為「類淋巴系統」的清理機制，可以清除腦中代謝廢物，該系統在我們睡著時明顯更加活躍。

It works by using cerebrospinal fluid to flush away toxic byproducts that accumulate between cells.

類淋巴會利用腦脊隨液將累積在細胞和淋巴管中的有毒代謝物質清洗掉。

Lymphatic vessels, which serve as pathways for immune cells, have recently been discovered in the brain, and they may also play a role in clearing out the brain's daily waste products.

淋巴管是免疫細胞的移動路徑，最新的研究發現腦中也有淋巴管分布，並也可能參與腦中代謝廢物的清理機制。

While scientists continue exploring the restorative mechanisms behind sleep, we can be sure that slipping into slumber is a necessity if we wanna maintain our health and our sanity.

隨著科學家們不斷地探索睡眠背後的生理恢復機制，我們能確定的事情是，「一覺好眠」是不可或缺的，如果我們還想要保持健康，並維持理智的話。