Regarding My Lack of Sleep It seems like genetic code determines how much time a person needs to sleep. But recently, a strange event happened. Until six months before, I needed eight hours of sleep to have a clear mind, but lately, I've noticed that three or four hours are enough. I didn't want to sleep for eight hours anymore, even though I knew it was bad for my health. What caused this transformation? My change of diet? My pillow? It's a complete mystery.