The ideal mattress should not contain any metal only natural fibres or natural Latex.
The above is a picture of me measuring a sprung mattress with a geomagnetometer to see to what extent the springs in the mattress are distorting the earths geomagnetic field.
The first graph is from the same area before placing the mattress and shows the contours of a normal geomagnetic field. The image below shows how the metal springs have distorted the earth's geomagnetic field into a geopathic zone.
Biological Effects Each static magnetic field bump or sink on the below geogram may speed up or slow down body fluids (blood and lymphatic) in exposed areas such as the brain, heart, lung, liver, legs etc. Sleep time exposure to the same sharp variations of magnetic fields for years may induce some chronic health effect. The World Health Organisation in a health criteria report recognises interactions between variations in static magnetic fields in cellular tissues to include an induction of electrical potentials and magneto hydrodynamic effects in the circulatory systems and by direct stimulation of nerve and muscle cells even under extremely weak thresholds.