Some Say Early Sleep Get Better Skin, Because The Skin

Some say early sleep get better skin, because the skin regeneration and organs work at between 11pm to 2pm?4pm? Those different time estimation just make me cannot trust. I start wondering those data is based on someone who sleep abou 11pm and wake up 8? How do our body know time! Isn’t it we tell them? I appreciate if someone can give me an answer that based on scientific evidence and explain a bit about how our bodies know time. :)