Memory foam, along with other materials that act like memory foam, is used in bedding products like mattresses and pillows due to its ability to adjust its form to exactly match your body. Memory foam is ideal because it avoid the pressure points that you feel when you sleep on a inner spring mattress, giving you a more comfortable night's sleep. When the memory foam is first manufactured, the cells that make up the foam are not fully open. In order to open up these cells, you need to break-in the mattress, a process that normally takes a few months, but can be sped up with a few techniques.
Remove the cover from the memory foam mattress. There will a zipper hidden on one side. This cover helps protect the mattress, but it also prevents heat from transferring to the mattress and opening up the cells. Keep the cover somewhere safe, as you will need to put it back on once the mattress has been fully broken in.
Walk on your mattress, preferably in concentric circles, for half an hour. Do this each night for the first week that you have your mattress. The constant rising and falling will speed along the breaking-in process.
Sleep in the mattress every night. Even if you find the original stiffness a little uncomfortable, having six to eight hours of your warm body on the mattress each night is the only way the mattress will get broken in.
Rotate the mattress after 30 days of use and then after 60 days of use. Do not flip it over; just rotate it from head to toe. You do this a little earlier if you feel that parts of your mattress are broken in, but others are still stiff.