What keeps you up at night? Pondering deep questions? Excitement about a big trip? Or is it stress about unfinished work, an upcoming test, or a dreaded family gathering? For many people, this stress is temporary, as it's cause is quickly resolved. But what if the very thing keeping you awake was stress about losing sleep? This seemingly unsolvable loop is at the heart of insomnia, the world's most common sleep disorder.
什麼事會讓你半夜睡不著覺？思考深奧的問題？期待重大旅行的到來？還是未完成的工作、即將到來的考試或是可怕的家族聚會所帶來的壓力？對很多人來說，這種壓力是暫時的，因為短期內就能解決。但要是真正讓你睡不著的，其實是對於沒有睡意的壓力呢？這種看似無解的迴圈，就是失眠症的核心，也就是世界上最普遍的睡眠障礙。
Almost anything can cause the occasional restless night. A snoring partner, physical pain, or emotional distress. And extreme sleep deprivation, like jet lag, can throw off your biological clock, wreaking havoc on your sleep schedule. But in most cases, sleep deprivation is short-term. Eventually, exhaustion catches up with all of us. However, some long-term conditions, like respiratory disorders, gastrointestinal problems, and many others, can overpower fatigue. And as sleepless nights pile up, the bedroom can start to carry associations of restless nights, racked with anxiety. Come bedtime, insomniacs are stressed. So stressed, their brains hijack the stress response system, flooding the body with fight, flight, or freeze chemicals. Cortisol and adrenocorticotropic hormones course through the bloodstream, increasing heart rate and blood pressure and jolting the body into hyperarousal. In this condition, the brain is hunting for potential threats, making it impossible to ignore any slight discomfort or nighttime noise. And when insomniacs finally do fall asleep, the quality of their rest is compromised.
半夜偶爾輾轉反側的原因有百百種。可能是枕邊人打呼、身體在痛、或是情緒低落。而極度的睡眠不足，像是時差，可能會打亂你的生理時鐘，把你的睡眠時間搞得亂七八糟。但大部分情況下，睡眠不足都是短期的。睡意終究會襲來。然而有些長期的問題，像是呼吸道疾病、腸胃問題等等，可能會超越疲憊感。而且隨著連夜失眠，房間可能開始會和躁動無法安睡的夜晚畫上等號。只要睡覺時間一到，失眠的人就開始焦慮。焦慮到大腦觸動壓力反應機制，大量釋放戰鬥、逃跑或停滯的激素到體內。皮質醇和促腎上腺皮質激素流過血液，增加心跳和血壓，連帶讓身體快速進入過度警覺的狀態。這種情況下，腦袋正與潛在的威脅交戰，使它無法忽視任何一丁點的不適感和夜間噪音。就算失眠者最終睡著了，休息的品質也被毀掉了。
Our brain's primary source of energy is cerebral glucose. And in healthy sleep, our metabolism slows to conserve this glucose for waking hours. But PET studies show the adrenaline that prevents sleep for insomniacs also speeds up their metabolisms. While they sleep, their bodies are working overtime, burning through the brain supply of energy-giving glucose. This symptom of poor sleep leaves insomniacs waking in a state of exhaustion, confusion, and stress, which starts the process all over again. When these cycles of stress and restlessness last several months, they're diagnosed as chronic insomnia. And while insomnia rarely leads to death, its chemical mechanisms are similar to anxiety attacks found in those experiencing depression and anxiety. So, suffering from any one of these conditions increases your risk of experiencing the other two.
大腦主要的能量來源為腦內的葡萄糖。在健康的睡眠情況下，我們的代謝會變慢，將這種葡萄糖留到睡醒後再用。然而 PET（註一）的結果顯示，腎上腺素除了會阻礙睡眠，也會加快失眠症患者的代謝速度。他們在睡覺時，身體還在超時加班，大量消耗著大腦內給予能量的葡萄糖。睡不著的症狀讓失眠患者雖然醒著但筋疲力竭、混亂且壓力大，而且會不斷循環。如果這種焦慮和無法休息的迴圈持續好幾個月，就會被診斷是慢性失眠。雖然失眠很少會導致死亡，但化學物質運作的機制和焦慮症雷同，能在憂鬱或焦慮症患者身上找到。只要有上述其中一種症狀，就會增加罹患另外兩種病症的風險。
Fortunately, there are ways to break the cycle of sleeplessness. Managing the stress that leads to hyperarousal is one of our best understood treatments for insomnia, and good sleep practices can help rebuild your relationship with bedtime. Make sure your bedroom is dark and comfortably cool to minimize threats during hyperarousal. Only use your bed for sleeping. And if you're restless, leave the room and tire yourself out with relaxing activities, like reading, meditating, or journaling. Regulate your metabolism by setting consistent, resting, and waking times to help orient your body's biological clock. This clock, or circadian rhythm, is also sensitive to light, so avoid bright lights at night to help tell your body that it's time for sleep. In addition to these practices, some doctors prescribe medication to aid sleep, but there aren't reliable medications that help in all cases. And over-the-counter sleeping pills can be highly addictive, leading to withdrawal that worsens symptoms.
幸好，的確有方法可以打破這種失眠迴圈。好好管理壓力以避免過度警覺是個淺顯易懂的失眠療法，好的睡眠習慣會幫助你重建睡眠品質。讓房間保持黑暗與舒適涼爽的溫度，以降低會造成過度警覺的威脅。床就只拿來睡覺。如果真的睡不著，就離開房間，做一些放鬆身心的事徹底放電，像是閱讀、冥想或寫日記。透過規律的作息調節新陳代謝，以重設你的生理時鐘。生理時鐘（或晝夜節律）對光源很敏感，所以夜晚避免強光，可以告訴你的身體該是時候休息了。除了做這些事以外，有些醫生會開藥幫助你入睡，但並沒有一種藥物百分之百有效。而且非處方安眠藥極容易上癮，停藥就會讓症狀更嚴重。
But before seeking any treatment, make sure your sleeplessness is actually due to insomnia. Approximately 8 percent of patients diagnosed with chronic insomnia are actually suffering from a less common, genetic problem, called Delayed Sleep Phase Disorder or DSPD. People with DSPD have a circadian rhythm significantly longer than 24 hours, putting their sleeping habits out of sync with traditional sleeping hours. So, while they have difficulty falling asleep at a typical bedtime, it's not due to increased stress. And given the opportunity, they can sleep comfortably on their own delayed schedule.
但在尋求任何治療前，你要先確定自己睡不著真的是失眠症引起的。大約有 8% 診斷出慢性失眠的患者其實是因為一種比較少見的遺傳問題－－睡眠相位後移症候群（簡稱 DSPD）造成的。有 DSPD 的人晝夜節律比 24 小時還長很多，使他們的睡覺習慣和傳統的睡眠時間不同步。雖然他們在正常人的睡眠時間睡不著覺，但不是因為壓力大所造成的。有機會的話，他們也能跟著自己比較慢的步調舒服地睡著。
Our sleeping-and-waking cycle is a delicate balance, and one that's vital to maintain for our physical and mental well-being. For all these reasons, it's worth putting in some time and effort to sustain a stable bedtime routine, but try not to lose any sleep over it.
我們的睡覺和清醒的循環是個脆弱的平衡，好好維持對我們的身心靈健康很重要。基於這些原因，花點時間和精力保持穩定的睡眠規律是很值得的，但不要太刻意維持反而失眠了。
註一：PET 的全稱為 Positron Emission Tomography，為正子斷層掃描，用來一次性取得全身的立體影像。
