Disclosed is a pressure relieving mattress that provides improved support and require a smaller air pump for inflation. The mattress includes a elongate support having a base and pair of spaced longitudinal side walls, the base providing a base surface extending between the side walls. A pressure relieving overlay lies over the base surface and an inflatable inlay extends between the base surface and the overlay. The inlay has a plurality of laterally extending inflatable cells in which at least some of the cells, in at least their un-inflated state, are wider adjacent their ends than a mid portion of the respective cells. The inflatable cells are supplied air or fluid by a supply extending longitudinally along the mattress, where the base is recessed to allow the supply to lie below the base surface. At least some cells having a narrow mid portion in an un-inflated state but which, when inflated, together define a substantially horizontal support platform. The uninflated volumes of at least some cells are in the shape of a bow tie when uninflated. There are two separate supplies for supplying alternate elements or alternate groups of elements and each supply lies in the recess.
