When Your Sleep Tracker Becomes the Problem

It is 3 a.m. Before you have even decided whether you are tired, your hand is reaching for your wrist. The score says 61. Restless. Two hours of deep sleep, which sounds bad, though you are not entirely sure what a good number would be.

And now you are properly awake.

Millions of us now wear something to bed that grades our sleep every morning. Most of us started for good reasons — curiosity, or a genuine hope of sleeping better. But for a fair number of people, the tracking quietly becomes part of the problem it was meant to solve.

Sleep clinicians even have a name for it: orthosomnia. The pursuit of perfect sleep data, at the cost of actual sleep.

The number knows less than you think

Here is something worth sitting with. Your watch is not watching your sleep. It is watching your wrist.

It notices movement and heart rate, then makes an educated guess. That guess is decent at telling whether you were asleep or not. It is considerably worse at noticing the minutes you lay awake — which is exactly what bothers you most. And the part people fixate on hardest, the breakdown into deep and light and REM, is the shakiest estimate of the lot. The formulas behind it are company secrets, so nobody outside the manufacturer can really check them.

None of this makes trackers useless. It does mean the number you are grading yourself against is softer than it looks on the screen. It arrives with two decimal places and the confidence of a lab result, and it is closer to a weather forecast.

Being told you slept badly makes you feel worse

This is the part that surprises people.

Researchers have tested it directly. Give someone made-up feedback about how they slept last night, and their performance on tests that day follows the feedback — not their actual sleep. Tell people they slept poorly and they do worse. Tell them they slept well and they do better. The belief does the work.

Which means a low score is not a neutral piece of information. It is a suggestion, delivered first thing in the morning, about how your whole day is going to go. You then spend that day noticing every yawn as evidence the watch was right.

Trying harder is the trap

Sleep is unusual. Almost everything else in life rewards effort. You want to get stronger, you train. You want to pass the exam, you study.

Sleep does the opposite. The harder you try to make it happen, the more awake you become. Clinicians call this sleep effort, and it sits at the center of most long-term insomnia. The worry about not sleeping is what keeps you from sleeping.

Now think about what a tracker adds to that. A nightly score. A target. A reason to check. A reason to lie in bed twenty minutes longer, hoping to bank a little more. If you were designing a device to increase sleep effort, you would build something that looks a lot like a sleep tracker.

For people who sleep fine, this is harmless — interesting, even. For someone already anxious about sleep, it pours fuel on the exact thing keeping them awake.

Two questions worth asking yourself

You do not have to throw the watch away. Tracking genuinely helps some people. It can show you that you are only giving yourself six hours in bed, or that your bedtime wanders by three hours across the week. Those are useful things to know.

The question is not whether you track. It is what the tracking does to you.

Does the number change how you feel about your day? If a bad score makes you cancel plans, or brace yourself for exhaustion before anything has actually happened, the tracker has stopped describing your life and started running it.

Do you check it in the night? If you do, stop. Look in the morning or not at all.

If either question made you uncomfortable, try the experiment nobody wants to try: take it off for two weeks. Or turn off the sleep notifications. Then judge your sleep the way people managed for thousands of years — by how you actually feel when you wake up.

Most people find the first few nights unsettling and the rest of the fortnight a relief.

When the worry is the real problem

Lying awake worrying about sleep is extraordinarily common. It is not a personal weakness, and it is not something you need to solve with a better device or a smarter algorithm. It is the engine of chronic insomnia — and it responds very well to treatment.

Cognitive behavioural therapy for insomnia, usually shortened to CBT-I, is the recommended first-line treatment ahead of sleeping pills. It works on exactly this loop: the monitoring, the effort, the fear of what one bad night will cost you tomorrow. It is not a list of sleep hygiene tips. It is a short, structured course of treatment, typically four to eight sessions, and most people notice real change.

If you have found yourself awake at 3 a.m., arguing with a small screen about your own sleep, that is a fairly clear sign the answer is not one more

當你的睡眠監測器，變成失眠的一部分

凌晨三點。你還未搞清楚自己是否真的疲倦，手已經伸向手腕。分數是 61。「睡得不安穩」。深層睡眠只有兩小時——聽起來很差，但其實你也不太確定「好」應該是多少。

然後，你就徹底清醒了。

現在有很多人戴著裝置睡覺，每朝起床都會收到一個關於自己睡眠的分數。大部分人開始時的動機都很合理：出於好奇，或者真心希望睡得更好。但對不少人來說，「監測」這件事本身，慢慢變成了它原本想解決的那個問題的一部分。

睡眠臨床上甚至有一個名詞形容這現象：orthosomnia——為了追求完美的睡眠數據，反而犧牲了真正的睡眠。

那個數字，知道的比你想像中少

有一點值得停下來想一想：你的手錶並不是在觀察你的睡眠，它是在觀察你的手腕。

它偵測到的是動作和心率，然後作出一個有根據的推測。這個推測在判斷「你有沒有睡著」這件事上，表現算不錯。但在偵測「你躺著清醒了多久」這方面，它明顯弱得多——而那偏偏就是最困擾你的部分。至於大家最執著的那一項，也就是深層睡眠、淺層睡眠、快速眼動（REM）的階段分佈，其實是整份報告中最不可靠的估算。背後的計算方式屬商業機密，外界根本無法真正核實。

這並不代表監測裝置毫無價值。但它提醒我們：你用來給自己打分的那個數字，比螢幕上看起來的樣子軟得多。它以精確到小數點的姿態出現，帶著化驗報告的權威感，但本質上更接近天氣預報。

「被告知睡得差」，本身就會令你更差

這一點通常最令人意外。

研究人員曾直接測試過：向受試者提供關於他們前一晚睡眠的虛假回饋，然後讓他們做當天的測試。結果，他們的表現跟「被告知的睡眠質素」一致，而不是跟實際睡眠一致。被告知睡得差的人，表現就差；被告知睡得好的人，表現就好。真正起作用的，是那個信念。

換句話說，一個低分並不是一項中立的資訊。它是一個在清早送到你手上的暗示，告訴你「你今天將會過得怎樣」。而你接著會用一整天去留意每一個呵欠，並把它當成手錶說得對的證據。

「更努力」正是陷阱所在

睡眠是一件很特別的事。人生中大部分事情都會回報努力：想變強壯，就去訓練；想考試及格，就去讀書。

但睡眠剛好相反。你愈努力想讓它發生，你就愈清醒。臨床上稱這為「睡眠努力（sleep effort）」，而它正處於大多數長期失眠的核心：真正令你睡不著的，是對睡不著的擔憂。

現在想想，監測裝置在這個循環上加了甚麼。一個每晚的分數。一個目標。一個不停查看的理由。還有一個令你多躺二十分鐘、希望「賺多一點」的理由。如果有人要設計一部專門用來增加睡眠努力的機器，做出來的東西大概就很像一隻睡眠監測手錶。

對本來睡得好的人來說，這沒甚麼壞處，甚至挺有趣。但對一個本來就為睡眠焦慮的人，它等於往那團火上再加油。

兩個值得問自己的問題

你不必立即把手錶扔掉。監測對某些人確實有幫助：它可以讓你發現，自己原來每晚只留了六小時在床上，或者一星期內的就寢時間相差達三小時。這些都是值得知道的事。

真正的問題不是「你有否監測」，而是「監測對你做了甚麼」。

那個數字，會否改變你對這一天的感覺？ 如果一個差分數會令你取消約會，或者在甚麼都還沒發生之前就已經準備好「今日一定會很累」，那麼裝置已經不再是在描述你的生活，而是在主導它。

你會否在半夜查看？ 如果會，請停止。早上才看，或者索性不看。

如果其中一個問題令你感到不安，不妨試一個大家都不太想試的實驗：把它脫下兩星期。或者關掉所有睡眠相關通知。然後用人類沿用了幾千年的方法評估自己的睡眠——憑你早上起床時實際的感覺。

大部分人會發現，頭幾晚有點不習慣，而餘下的兩星期，是一種解脫。

當「擔憂」才是真正的問題

躺在床上擔心自己睡不著，是極其普遍的事。這不是性格上的軟弱，也不是需要用更好的裝置或更聰明的演算法去解決的問題。它正是長期失眠的引擎——而且，它對治療的反應非常好。

失眠認知行為治療（一般簡稱 CBT-I）是國際指引建議的第一線治療，優先於安眠藥。它處理的正好就是這個循環：過度監測、過度用力，以及對「睡不好明天會有甚麼後果」的恐懼。它不是一張「睡眠衛生」貼士清單，而是一套短期而結構化的治療，通常為期四至八節，大部分人都會感受到實質改變。

如果你曾在凌晨三點，對著一個小小的螢幕爭辯自己的睡眠——這已經是一個相當清楚的訊號：答案並不在於「再多一個數字」。