Translation guide
The state of not getting enough sleep, often due to lifestyle, work, or medical reasons. Japanese expressions range from casual to medical, with some emphasizing lack of sleep and others the resulting drowsiness.
To describe the condition of not having slept enough, in everyday conversation.
The most common and neutral term for sleep deprivation or insufficient sleep. Used in both casual and formal contexts.
最近、睡眠不足で集中できない。
Lately, I can't concentrate because of sleep deprivation.
睡眠不足が続くと健康に悪いですよ。
Continuous sleep deprivation is bad for your health.
A more casual, colloquial version of 睡眠不足. Commonly used in daily speech.
昨日あまり寝られなくて、寝不足なんだ。
I couldn't sleep much last night, so I'm sleep-deprived.
Literally 'haven't slept.' A very casual way to say you're sleep-deprived, often implying you pulled an all-nighter or got very little sleep.
昨日徹夜で、全然寝てない。
I pulled an all-nighter yesterday and haven't slept at all.
To refer to sleep deprivation as a medical condition or in formal writing.
Medical term for sleep deprivation syndrome. Used in clinical settings.
睡眠不足症候群は、慢性的な睡眠不足によって様々な症状を引き起こします。
Sleep deprivation syndrome causes various symptoms due to chronic lack of sleep.
Total sleep deprivation, often used in scientific experiments or extreme situations. Not used in daily conversation.
断眠実験では、参加者は24時間以上起き続けることを求められた。
In the sleep deprivation experiment, participants were required to stay awake for over 24 hours.
To focus on the feeling of sleepiness or exhaustion caused by lack of sleep.
Adjective meaning 'sleepy' or 'drowsy.' The most direct way to express the result of sleep deprivation.
睡眠不足で、一日中眠かった。
I was sleepy all day because of sleep deprivation.
Literally 'not having slept enough.' Emphasizes the insufficiency of sleep.
まだ寝たりない感じがする。
I still feel like I haven't slept enough.
Avoid directly translating 'sleep deprivation' as 睡眠剥奪 (すいみんはくだつ). This is not a natural Japanese expression. Use 睡眠不足 instead.