most likely a doctor. many believe in his condition soething floppy like a matress will strain the back. flatter more stable things as in the floor are thought to keep the spine in line and lower pain levels.
Just my opinon or thought
most of the time i have tons of problems sleeping. Many things work then dont work. I worked 1st shift for awhile and it screwed me up hardcore. Sometimes i just stay awake so long then i have to sleep. eventually u cant control it. its said that in order to torture people the militarywill allow them to sleep 4 or 5 hours. its ten times as bad as staying awake for a couple days.