Sweet Dreams on a Hard Surface: The Ergonomics of Sleep (2006) (zafu.net)

I slept for three years on a slab of concrete with a folded wool fire blanket as a mattress. On top of it I had sheets and a top blanket and a regular pillow. My roommates thought I was crazy, but after a few days of adjusting to it, I found it to be the most comfortable sleep I had experienced up until that time. All back pain disappeared. That was thirty years ago. I sleep on a regular American bed now, but any time I’ve had any issue with back pain or core muscle strain, I think back on that concrete slab with fond memories.

Whenever I have back pain, I switch to sleeping on a foam camping pad on the floor. Works great, but annoys the wife

I'm sure there are lots of people who would benefit from sleeping on their back on a firm surface. I have mild positional sleep apnea. When I sleep on my back I stop breathing a few times an hour. Sleeping on my back might improve some things but isn't good for me having a restful nights sleep.

Bodyweight seems like a major factor never discussed when looking at mattresses or sleeping positions. As a teen I remember the point where a sleeping bag on a wooden floor stopped being comfortable.

When I was in China for a few months, the hardness of the bed surprised me. The mattress, such as it was, was just a plywood box covered in a thin layer of ticking.

I found it extremely difficult.to find a comfortable sleeping position. Never got used to it.

Body can can sleep well anywhere if tired enough. Problem is trying to sleep when you're not, especially if you have difficulties falling asleeping.

I remember a few years ago a designer/researcher (Japanese if I remember) came up with a bean-bag type bed that they claimed was a more natural fit for the way humans sleep evolutionarily.

If I search for that now I get either mattress 'review' sites (aka sales channels), or kinky videos.

edit: aha, found it: https://www.theguardian.com/world/2016/jun/21/chimpanzees-be...