Ginny and I have worn devices that monitor our sllep, letting us know the amount of light
sleep and deep sleep each night. I'm not sure about what those sleeps define but when I get more deep sleep I feel better and more alert.
If I don't get enough sleep I take a 22 minute nap. Invariably those naps are all deep sleep. The naps all take place in a confined space, on the couch. Is there something about a small space that results in deep sleep?
We find that we sleep particularly well in the trailer, our 'little bigger than a twin bed'. Is it because of the confined space?
The reality that all the big beds we seem to demand these days are relatively modern. Of course most of us have become bigger than people used to be.