Sleeping on a hard surface, eh? Any interesting links or comments on that? I've been wondering lately about how habitual shoelessness might ease back pain, but I don't know how much of an effect shoes have on the back.
I vaguely remember a study about an Asian country where they mainly sleep on floor mats, and they have less back problems there. Can't seem to find it now though. I'm mostly just seeing a lot of anecdotes. Maybe it's one of those things where that varies between people. Can't find any real studies on it though. For me, though, it definitely helped my posture and back problems. I don't know much about barefootedness, aside from that you shouldn't run barefoot. I'm sure the story's different if you're in some remote village in Kenya though. Or in that one African country, where they'd just keep pace with gazelles until the gazelles collapsed of exhaustion. Persistence hunting is extreme.