The memory foam mattress pad is the talk of the bedding industry because there is no other sleeping surface that responds to the weight of your body. It is easy to get confused surrounding all the hype and promotions concerning memory foam mattress pads. An important question to ask is do they actually work as advertised. It works the best when it is layered over a firm mattress since it is too soft to act as the only thing you sleep on. So it is best used on top of existing bedding. One of the ways that memory foam mattress pads are different is that the foam cells deform when compressed is that the air pressure is spread to adjoining cells because it is an open cell material, which means the cells have holes in them.