This only sounds like a small amount — especially when you compare it to cats or other animals that spend more than half of their lives unconscious. But the real amount of time Americans spend asleep is less than a third of their lifespans. Think about it — this math isn’t hard to do. If you sleep for eight hours a night and there are 24 hours in a day, that’s one third of every day spent asleep. Who do you know that actually sleeps a consistent eight hours?