matress are around 40, maybe 50kg/m3. water is 1kg/dm3, and acording to this website (https://www.aqua-calc.com/page/density-table/substance/human-blank-body h

matress are around 40, maybe 50kg/m3. water is 1kg/dm3, and acording to this website (https://www.aqua-calc.com/page/density-table/substance/human-blank-body https://www.aqua-calc.com/page/density-table/substance/human...) human is arround 1000kg/m3 which make sense. So, yes matress is light compared to human, I guess it does nothing to the sensor pad.