Additional Aspects to Consider in Choosing a Mattress
Besides the comfort layers and the support layers of your mattress, there are a few other choices you will need to make to find your perfect mattress. These are not directly connected to comfort/ pressure relief and support/ spinal alignment but they can play a very important role in your choice of mattress. Here are a few of them and some comments that may help you decide on the final elements that your "perfect mattress" should be made of.
Mattress Feel
Breathability and Temperature Regulation
There are some people who naturally sleep hotter than others and for some people this can be a real issue. In general, natural fibers and innersprings are the most breathable materials as the allow air to flow through them and evaporate any moisture. Wool is a good choice in the quilting of your mattress as it is very breathable and helps to regulate your temperature very well. Many people will also use wool as part of a mattress pad as this way it can be more easily replaced than a full mattress cover if it compresses and firms up your mattress a little too much. Bear in mind that any layer of natural fiber will tend to make the foam layers underneath them a little firmer, especially as they compress, however as long as it is not too thick this should not present real problem with higher quality materials and construction which are designed to delay the compression for as long as possible. Natural fibers and their many benefits in a quilting layer are often a good tradeoff for better temperature regulation and better quality sleep.
In terms of materials themselves, memory foam tends to sleep the hottest as it forms the deepest cradle and is not as open celled as other types of polyfoam which means that air does not flow through it as easily. Newer generation or "breathable" memory foams are better in this regard although they too are not as breathable as other foams. Polyurethane is the next most breathable foam and for those who sleep hot it presents fewer issues of temperature regulation. Dunlop latex is the next most breathable foam and is much more breathable and temperature regulating than polyfoam. Finally Talalay latex is the most breathable of all foams and rarely represents an issue for those who sleep hot. There are also special "formulations" of Talalay latex that have an added ingredient (Celsion is one of them) which improves temperature regulation even further. There are also several fabrics that are used in mattress ticking (CoolMax and Outlast are two of them) which can help to regulate temperature while sleeping on a mattress. Just be a little wary of "cooler sounding" labels attached to "hotter sleeping" materials.
Mattress Thickness Consideration
Understanding mattress thickness
Generally, this depends somewhat on weight. Thicker mattresses if properly constructed can provide a greater range of support for different sleeping positions ... especially if you are on the heavier side. If you are very light ... then thinner is fine. In an all latex mattress for example 6-7" would normally be fine for someone who was very light. For someone of average weight then 8-9" is usually fine and for someone who is heavier then an extra inch or two could make a difference especially if you sleep on your side. It would take a very heavy person (over 400 lbs) though to "bottom out" on even 8" of quality foam (except memory foam of course) and the greater thickness would not be for preventing bottoming out but to provide a wider range of comfort and support for a heavier person who slept in several positions. Bear in mind too that high profile innersprings which offer a greater range of support for combination sleepers can be 7" or more in height and with a quilting layer and 4" of foam on top you will have a mattress of about 12" so the type of layers inside will also play a role in the overall thickness of your mattress. 2 sided mattresses will also be thicker (and more desirable as they last longer) since they have a comfort layer on both sides however they make an excellent choice. It is a shame that they have become so much less common for the sake of higher profits and with the story attached of "less maintenance" when the story has so often led to premature wear in lower quality materials or constructions.
Safety Considerations