This is where words like cozy, comfortable and 'sleeping on a cloud' come in... It is also where words like dips, peaks and valleys come in.
Isn't it maddening... You find the perfect mattress. You get it home and sleep well on it for a few years, but then those ruts start to form where you sleep - often times, even if you are rotating it regularly like you're supposed to.
Why does this happen?
Because it is IMPOSSIBLE to keep polyfoam comfort layers from compressing. No matter what you do, expect the foam in your mattress to eventually form a dip almost as deep as the foam is thick - especially when you're laying on top of it.
Of course, for many mattresses - this mean that a 'peak' also develops in the center.
There ARE things you can do to minimize this phenomenon:
1) Sleep on the ENTIRE mattress if you can. For instance, when you take a nap during the day by yourself, sleep in the middle instead of your usual 'side'.
2) ROLL across the whole thing from top to bottom every once in awhile. This will help to 'fluff the foam back into place'.
3) If you've got a badly-dipping mattress and company is coming... Flip the whole thing over for a few days or even a couple of weeks before they arrive. Or, if this is your mattress, flip it over when you go out of town for the weekend.
While this may compress some of the overall foam on top; gravity will help work the rut out for a more even sleep surface. The foam will fluff up a bit more after the mattress is set back upright. You don't usually sleep on the parts of the foam that don't compress, anyway. And remember, you can always add more cush via a topper.
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