Sleeping is the bridge between life and death. You pass out but still function because you're alive, alive enough to wake up from the sleep. But you're also half dead too, because you're in one solitary place of which to sleep in.

So technically speaking, everyone has died, you've experienced death, but one which you can wake up from at any given time. That is unless, you don't wake up anymore then you're definitely dead on a permanent basis.