How much do I need to sleep? It depends on your age
https://edition.cnn.com/2021/07/27/health/how-much-do-i-need-to-sleep-wellness/index.html
Among high school or junior high school education or black companies in Japan, studying more by cutting sleeping time to an extent is taught to be ideal diligence. But, this kind of the conventional mindset seems to be deteriorating their brains.
