深夜テンション (しんやてんしょん, shinya tension/tenshon) means “midnight high”, i.e. the state of feeling high, bold and somewhat irrational when you’re staying up late at night (with or without drinking). During the midnight high, you often feel more positive than usual and find anything, even lame jokes or conversations, very hilarious. Some people end up going overboard and doing something they regret the next day, e.g.
- impulsively buy expensive and unnecessary items on Amazon
- write a lengthy and poetic post on social media
- send an overly emotional text like “I love you” or “I can’t help thinking about you” to one’s crush
and so on. This phenomenon is considered to be caused by the rise in dopamine following sleep deprivation.
“深夜” means “midnight”, where “深” and “夜” mean “deep” and “night”, respectively. “テンション” is a loanword from “tension” in English, but its meaning is completely different from the English word. See the following section for how it is used in Japanese.
Meaning of “tension” in Japanese
In Japanese, テンション (tension) describes a person’s emotional state or feeling. For instance, “テンションが高い” or “ハイテンション”, which literally means “tension is high” or “high-tension”, actually means “(someone) is excited, giddy or delighted”. Similarly, “テンションが低い”, which means “tension is low”, indicates that someone is down, gloomy, or depressed. Therefore, you may hear some Japanese people saying “You are high-tension!” in English, which you should interpret as “You look excited!” or “You look delighted!”.
It is my 黒歴史 that I uploaded my dance video on YouTube during “midnight high”.
You should avoid deciding something important when you are in “midnight high” (temporary high at midnight).
If you write a blog during the “midnight high”, you most likely regret that the next morning.
During “midnight high”, even lame jokes can sound very funny
Synonyms in English: temporary high at midnight
Related words and phrases: 深夜 (midnight), テンションが高い (excited), テンションが低い (down)