Abstract: A body support apparatus is disclosed as having alternatingly inflatable and deflatable cells and uninflated resilient body support material positioned between the cells. The cells are inflated by pressurized fluid such as air under the control of a control device utilizing diaphragm means responsive to the pressurized fluid to determine the inflation and deflation time periods and connect and disconnect the pressurized fluid to the cells. During the time period in which the cells are inflated, the support of a body will be provided by the uninflated support material. During the time that the cells are inflated above the support level of the uninflated support material, the cells will support the body.