Yugioh Episode 31 Keiths Machinations (1) - a Cinéma video. USA Character Project. The Uncanny Valley. Zombie in a Penguin Suit Isn't What You're Expecting... Watch It. Do you read the walking dead comics?
They touched on it lightly in the TV series, but in the zombie fiction for that, all the body's and brain's functions are completely inactive apart from the need to feed, breathing and shambling, meaning they dont really need to sleep. but hey, its only fiction.....right? It is only fiction, because that would be impossible. The brain needs sleep to sustain itself, otherwise you won't be able to do a lot of things— including focusing. Zombies need focus to kill other humans- as the whole shambling thing only makes sense of the disease messes up your brain's ability to properly walk or destroys muscle tissue.