03-011 · EVIDENCE B · LOW-RISK READING
Take a 10‑minute nap in the afternoon — don’t sleep half an hour
下午困了就睡 10 分钟，不要睡半小时
It costs nothing. Just set aside 10 minutes and find a place where you can lie down or recline.
A 10‑minute nap gives an immediate boost of alertness that lasts about two and a half hours. A 5‑minute nap provides almost no benefit, while a 20‑minute nap only starts to help after roughly half an hour. Sleeping 30 minutes brings on sleep inertia — you’ll feel groggy right after waking, making performance worse than if you hadn’t napped at all.
B
Move “Take a 10‑minute nap in the afternoon — don’t sleep half an hour” to Future Me's calendar
The excuse
The routine already works until the day the source says it may not.
What feels good now
Today I keep a few minutes and avoid interrupting my default routine.
What the source says
The source summarizes the return this way: “A 10‑minute nap gives an immediate boost of alertness that lasts about two and a half hours. A 5‑minute nap provides almost no benefit, while a 20‑minute nap only starts to help after roughly half an hour. Sleeping 30 minutes brings on sleep inertia — you’ll feel groggy right after waking, making performance worse than if you hadn’t napped at all.” Evidence grade B. The original states the population, caveats, and sources; this is not a personal forecast.
Open the original entry, check who the evidence applies to, then pick one small step that fits.
THE ENGLISH EDITION
Original recommendation and evidence
11. Take a 10‑minute nap in the afternoon — don’t sleep half an hour
Cost: It costs nothing. Just set aside 10 minutes and find a place where you can lie down or recline.
In plain terms: A 10‑minute nap gives an immediate boost of alertness that lasts about two and a half hours. A 5‑minute nap provides almost no benefit, while a 20‑minute nap only starts to help after roughly half an hour. Sleeping 30 minutes brings on sleep inertia — you’ll feel groggy right after waking, making performance worse than if you hadn’t napped at all.
Benefit: After a night of insufficient sleep, a 10‑minute nap quickly reduces drowsiness, fatigue, and improves energy and mental performance; some of these effects persist for up to 155 minutes. A 5‑minute nap yields virtually no benefit, and the advantages of a 20‑minute nap appear only after 35 minutes. A 30‑minute nap first causes sleep inertia, so performance is actually poorer right after waking, before any improvement occurs.
Evidence grade: B
Sources: Brooks & Lack (2006). A brief afternoon nap following nocturnal sleep restriction: Which nap duration is most recuperative? Sleep. <https://doi.org/10.1093/sleep/29.6.831>
Notes: Only one laboratory study exists, and its participants were healthy young adults. If you can’t fall asleep, there’s no need to force it; there’s no research showing any benefit from simply lying down with eyes closed for 10 minutes. Naps longer than an hour have been linked to higher mortality and increased risk of coronary heart disease — see Section 2, Item 38 (keep naps under 30 minutes). 〔37〕
Read the complete Chinese source and notes
11. 下午困了就睡 10 分钟，不要睡半小时
成本: 不花钱。花 10 分钟，再找一个能躺下或者趴着的地方。
说人话: 10 分钟的小睡当场就能提神，效果能撑两个半小时。睡 5 分钟基本没用。睡 20 分钟要等半小时以后才见效。睡 30 分钟，醒来先有一段发懵，那阵子表现比不睡还差。
收益: 在前一晚没睡够之后，10 分钟的小睡能立刻改善困倦、疲劳、精力和脑力表现，一部分好处维持到 155 分钟以后。睡 5 分钟几乎没有好处。睡 20 分钟的好处要等 35 分钟以后才出现。睡 30 分钟以后先有一段睡眠惰性：刚醒那阵表现反而更差，之后才改善。
证据等级: B
来源: Brooks & Lack (2006). A brief afternoon nap following nocturnal sleep restriction: Which nap duration is most recuperative? Sleep. <https://doi.org/10.1093/sleep/29.6.831>
备注: 只有一项实验室研究，受试者都是健康年轻人。睡不着也不必勉强。闭着眼躺 10 分钟有没有用，没有研究支持。午睡睡过一小时反而和更高的死亡率、冠心病风险连在一起，见第 2 节第 37 条（午睡控制在半小时内）。
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