An Overview of Memory Foam as a Mattress Comfort Layer

Memory foam, can be an excellent choice for pressure relief. It is only suitable however for use as a comfort layer in a mattress and is used over other support layers, preferably high quality such as HR polyfoam, innersprings, and latex. It has some unusual qualities which leads to both its strengths and its weaknesses.

Interestingly enough, memory foam shares some of the qualities of waterbeds and airbeds in that it partly flows away from pressure rather than compresses underneath it. This and its ability to respond to pressure in only the area of the pressure and its ability to absorb energy give memory foam some genuine advantages. What has often been forgotten though in the massive advertising and misinformation that surrounds it is that it shares most of these advantages with other materials which accomplish the same thing in different ways. Many of these "informed comparisons" are never made because of the amount of misinformation that exists in the industry in general. It also has some drawbacks that are also unique and it tends to be a love it or hate it type of material.

When you lie on a memory foam mattress, it will soften with heat and pressure and become semi solid. It is also less open celled than other foams so the air inside the foam takes more time to both move away from pressure and also to come back "on the rebound". This transformation from elastic behavior to viscous (liquid) behavior and back again in combination with the more closed cell structure of the foam results in a slower response to changing pressure and shape and is why it is often called "slow response foam".

Pressure relieving qualities of memory foam. 

Because it is able to "flow" around pressure, it forms itself very exactly around your body profile, it does a very good job at relieving pressure as part or all of a comfort layer. This is its main strength. It is considered by many to be the best at pressure relief however while there is no disputing that it is very good, whether it is better than some other materials such as latex or buckling column gel is open to question and most of these claims are not supported by real evidence but simply repeated over and over again until they are believed. They are all very close in this regard. It is also a "dead" feeling foam and absorbs energy that is applied to it so it has little to no resilience as opposed to latex, polyurethane, innersprings, or even many natural fibers and so is not nearly as springy or lively. This too is attractive to some who do not move around a lot or change positions as often throughout the night. It is also very good at isolating movement between sleeping partners because of its ability to respond to pressure in a very local area. This too it shares with latex and to a lesser degree some higher quality polyfoams. Finally it is attractive to those who like sleeping "in" their mattress rather than "on" their mattress as it forms a deeper pressure relieving cradle than other foams or materials.

While memory foam has real strengths in the area of pressure relief and movement isolation, it also has some drawbacks because of its very different qualities and structure. It tends to sleep hot for those who are sensitive to this and even the newer generation more breathable memory foams are not as breathable or open celled as other types of foam. Because it absorbs energy, has little resilience and is a poorly supportive material and relies on the layers underneath to provide support and spinal alignment. This may also mean that with thicker layers there is little support for the lumbar area which does not come in firm contact with the support layers and will not be held up well by a foam that "melts" under pressure. It can also present problems for those who prefer some "assistance" in their movements on a mattress as it responds very slowly to new and changing positions and some have described it as a little like "sleeping in sand". Finally it is difficult to control how far you sink into a memory foam layer as it may soften over the course of the night and what started out as correct spinal alignment could turn into a "hammock" position and a backache by morning. A final drawback of memory foam, and this is especially true of memory foam made by unknown manufacturers with unknown certifications, is that it can smell very bad for significant periods of time and in some cases this smell and the outgassing that produces it can create some health concerns.

A Recommendation for Memory Foam

If you choose to go in the direction of memory foam, I would recommend that you use the minimum thickness that is suitable for your needs and preferences. I would also consider combining it with other types of material in your comfort layer, which can be very comfortable for some, so you can take advantage of its strengths without being as affected by its weaknesses. Finally make sure that you are choosing a high quality memory foam made by a reputable manufacturer that meets 3rd party testing standards and publishes that they have done so. There are many of these who produce high quality memory foam for a very reasonable price and it is not necessary to purchase either overpriced memory foam to get good quality or to purchase questionable qualities of memory foam which have not been subjected to testing.

Memory foam does a great job as far as its strengths but some important trade-offs are required in order to take advantage of these strengths. The popularity of memory foam has been driven to such a large degree by "advertising copy" and misleading information that it is difficult to get accurate comparative information about it anywhere on the web as the same stories are repeated endlessly. For example ... it was never even used in the space program because of its drawbacks and yet is is almost always connected to NASA to create the impression that it was used by astronauts who are subject to high G forces. It is true that NASA was the source of the original attempts at producing a formula that worked however they did not continue its development. It is also difficult for consumers to compare it to materials that offer similar benefits as it is so often compared to materials or firmer versions of materials that do not have the same pressure relieving properties that many are unaware that there are alternatives available that have some of these same strengths without some of the drawbacks.

In any case, memory foam or a combination of memory foam with other pressure relieving materials can be very comfortable. Just make sure you do a little homework so you are not subject to the misinformation that exists and end up paying a lot of money without knowing exactly what you are purchasing.

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Aldatx's Avatar
Aldatx replied the topic: #2 04 Dec 2017 12:58
can you point me in the direction on where to find quality memory foam
phoenix's Avatar
phoenix replied the topic: #3 04 Dec 2017 13:23
Hi Aldatx,

While I don't maintain a complete listing of all of the memory foam component suppliers (it would be much too large a task in an ever-changing market), there are some sources listed in the component post here . At least it would give you a good start.

cschell's Avatar
cschell replied the topic: #4 05 Feb 2018 13:25
I have Dixie Foam's Thermopedic from 2005 that needs to be replaced.. I seem to need the memory foam because of hip pain when I lie on layex. Their newer memory foam is with gel, and is comprised thusly:

Gel memory topper - 3"/4 lb density
Base layer - 5"/2.8 lb density, 35 ILD

It feels comfortable, relieves pressure. Based on your recommendations, is this adequate support for the lumbar region? I'm 5'1" and 108 lbs. I sleep on my side.

Does this gel topper offer cooling? Thanks.
phoenix's Avatar
phoenix replied the topic: #5 06 Feb 2018 00:37
Hi cschell.

Welcome to our forum :)!

I have Dixie Foam's Thermopedic from 2005 that needs to be replaced.

It seems that you got a very good life span out of your previous mattress before it needed to be replaced and given that it worked so well for you it would not be unreasonable to want to replace it with something similar. I am not familiar with a bed from 13 years ago and I would not know if what you are currently considering would be comparable with the previous one. This is a question that you may wish to ask the manufacturer themselves.

Does this gel topper offer cooling?

Memory foam does a very good job at minimizing motion transfer, but it will generally be the least breathable and most insulating of the foam comfort materials, so temperature can be an issue. If temperature regulation is of concern you’d want to make sure that you don’t choose something with so much memory foam on top that you sink in too deeply. Even the newer generation of more breathable gel memory foams are not as breathable or open celled as other types of foam. Because it absorbs energy, has little resilience and is a poorly supportive material and relies on the layers underneath to provide support and spinal alignment. Even though you are light and petite with thicker layers there is little support for the lumbar area which does not come in firm contact with the support layers and will not be held up well by a foam that "melts" under pressure.

Regarding cooling memory foam claims, you can read more about phase change materials in post #9 here and at the end of post #4 here ) and you can read more about the various different types of gel foams in post #2 here . In general terms gel foams will tend to have a temporary effect on temperature while you are first going to sleep until temperatures equalize but have less effect on temperature regulation throughout the course of the night.

Copper itself is a very thermal conductive material so it would make sense that copper fiber infused memory foam (or other types of more advanced thermally conductive materials such as graphite) would be a little more effective than the gel that is more commonly used but it would also depend on the amount of copper that was in the memory foam.

In very general terms ... gel and/or other thermal conductive or phase change materials can have "some effect" on the sleeping temperature of a particular material but how much of an effect they will have and how long the effect will last will depend on the specific formulation of the material and on the "combined effect" of all the other materials and components of the sleeping system including your sheets, mattress protector, and bedding. Many thermal conductive or phase change materials tend to have a more temporary effect when you first go to sleep at night or over the first part of the night than they will over the entire course of the night.

As it seems that you would like to replicate the feel of your old mattress, I would suggest that you reach out the manufacturer as they would be the best to best match and provide the appropriate support that would keep you in neutral alignment throughout the night.

cschell's Avatar
cschell replied the topic: #6 06 Feb 2018 07:39

Thanks for your response. I was trying to find out if you thought the specs of the new mattress, based on the comments in your article, would provide adequate lumbar support for a petite woman, 108 pounds. I didn't expect a comparison with an old product.
Gel memory topper:3"/4 lb density
Base: 5"/2.8 density, 35 ILD

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