The magic 90-minute sleep cycle! - Psychology Express

We are almost all taught from childhood to "get eight hours of sleep", have you ever doubted the correctness of this education? Have you ever slept for 8 hours and still felt tired? Ever slept for four and a half hours and felt refreshed?

This is an article that has attracted a lot of attention on the Internet, in a sense, it overturns people's long-held unscientific understanding of sleep. People who sleep naturally without any other external dry scratching will wake up on average after a multiple of 90 minutes, and the human sleep cycle is about 90 minutes. Sleep time as long as a multiple of 90 minutes, you can greatly improve the quality of sleep. Humans are naturally better suited to polyphasic sleep, which involves sleeping multiple times a day, rather than the monophasic sleep we are used to (sleeping at night and working during the day). _psytopic.com