I have a ridiculously bad back (as does my father) and have developed a large variety of tricks to minimize pain. One is I sleep on a maximally firm futon. When

I have a ridiculously bad back (as does my father) and have developed a large variety of tricks to minimize pain. One is I sleep on a maximally firm futon. When I go on trips, if the bed I’m sleeping in is too soft, I lay a blanket on hard wood and sleep on it. I sleep very well this way. A slab of granite would be fine as a bed. If I was ever put in a dungeon, at least I would sleep soundly on the concrete floor!