>>48387636There's considerable genetic variation in the amount of sleep people need. Partly it's a function of how quickly you can enter REM, which is the most restful phase of sleep. Uberman and similar sleep schedules work by training your body to get into REM faster.
This article title sounds like it's describing 10ma:
https://www.bbc.com/future/article/20150706-the-woman-who-barely-sleeps