Just what the title says, how much sleep do you need to function normally throughout the day? It's been a while since I've seen a solid 8 hours of sleep. I usually get between 3-4 hours a night, but last night I went to bed about 1:45ish and was wide awake at 4 A.M. which tells me my body has gotten use to a lack of sleep. Probably not a good thing, but I don't feel tired at all, and I know I'll be up until the wee hours again tonight. How much do you need not to be a walking zombie?