「夜間モードは良質な睡眠の鍵か？」

"Is Night Mode the Key to Better Sleep?"

スマホの「夜間モード」は、寝る前のブルーライトによるメラトニン抑制を和らげる効果が期待されますが、完全な解決策ではありません。質の高い睡眠を得るためには、画面の明るさを下げたり、就寝前にスマホを手放すことも重要です。

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Is the "night mode" on smartphones really effective?

One reason you might struggle to fall asleep is your smartphone usage before bed. The blue light emitted by smartphones and computers is said to suppress the secretion of melatonin, a hormone that regulates your internal clock, leading to a poor wake-up experience the next morning.

In an experiment conducted in 2015 by Professor Charles Czeisler and his team at Harvard Medical School, it was reported that participants who viewed screens with high levels of blue light before bedtime took an average of about 10 minutes longer to fall asleep.

The feature designed to reduce blue light is called "night mode." Regular displays emit a bluish light similar to daylight, but when night mode is activated, the screen's color temperature decreases, changing to a warm tone with a yellowish hue. It is believed that reducing the blue component weakens the suppression of melatonin to some extent.

However, relying solely on night mode is not a complete solution. By also lowering the screen brightness and putting down your smartphone an hour before bed, you can expect to achieve better sleep quality.

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by F_chika
作成:2025/04/22 15:24
レベル:中上級 (語彙目安:4000〜6000語)

# 「夜間モードは良質な睡眠の鍵か？」
## "Is Night Mode the Key to Better Sleep?"

![thumbnail](https://eigobox.s3.ap-northeast-1.amazonaws.com/g/edd4b09d37c393d07ce95190676474f51bf42636.png)

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Is the "night mode" on smartphones really effective?  
One reason you might struggle to fall asleep is your smartphone usage before bed. The blue light emitted by smartphones and computers is said to suppress the secretion of melatonin, a hormone that regulates your internal clock, leading to a poor wake-up experience the next morning.  
In an experiment conducted in 2015 by Professor Charles Czeisler and his team at Harvard Medical School, it was reported that participants who viewed screens with high levels of blue light before bedtime took an average of about 10 minutes longer to fall asleep.  
The feature designed to reduce blue light is called "night mode." Regular displays emit a bluish light similar to daylight, but when night mode is activated, the screen's color temperature decreases, changing to a warm tone with a yellowish hue. It is believed that reducing the blue component weakens the suppression of melatonin to some extent.  
However, relying solely on night mode is not a complete solution. By also lowering the screen brightness and putting down your smartphone an hour before bed, you can expect to achieve better sleep quality.

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スマホの「夜間モード」は本当に効くのか？  
布団に入ってもなかなか眠れない──その理由のひとつが、寝る前のスマホかもしれません。  
スマホやPCの画面が放つ青色光（ブルーライト）は、体内時計をつかさどるホルモン「メラトニン」の分泌を抑え、翌朝の目覚めを悪くすると言われています。  
2015年にハーバード大学医学部のチャールズ・ツァイスラー教授らが電子書籍端末を用いて実施した実験では、就寝前にブルーライトを多く含む画面を見た被験者は入眠までの時間が平均で約10分延びることが報告されています。  
このブルーライトを和らげるために搭載されている機能が「夜間モード」です。通常のディスプレイは昼間の太陽光に近い青白い光を多く含みますが、夜間モードをオンにすると画面の色温度が下がり、暖かみのある黄みがかったトーンへと変化します。青色成分が減ることでメラトニン抑制はある程度弱まると考えられています。  
もっとも、夜間モードだけで万事解決とはいきません。画面の明るさそのものを落とす／寝る1時間前にはスマホを手放すといった使用時間の見直しを併用することで、より質の高い睡眠が期待できます。

Is the "night mode" on smartphones really effective?  
One reason you might struggle to fall asleep is your smartphone usage before bed. The blue light emitted by smartphones and computers is said to suppress the secretion of melatonin, a hormone that regulates your internal clock, leading to a poor wake-up experience the next morning.  
In an experiment conducted in 2015 by Professor Charles Czeisler and his team at Harvard Medical School, it was reported that participants who viewed screens with high levels of blue light before bedtime took an average of about 10 minutes longer to fall asleep.  
The feature designed to reduce blue light is called "night mode." Regular displays emit a bluish light similar to daylight, but when night mode is activated, the screen's color temperature decreases, changing to a warm tone with a yellowish hue. It is believed that reducing the blue component weakens the suppression of melatonin to some extent.  
However, relying solely on night mode is not a complete solution. By also lowering the screen brightness and putting down your smartphone an hour before bed, you can expect to achieve better sleep quality.

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