Memory Foam Mattress Review-Definitely The Ultimate Pressure Relieving Material..But Which Is Best, And Where Can I Get A Great Deal?
The problem with many conventional mattresses is that they just don't conform or fit well to your body's shape and contour. They are either rigid and resist the curves of your shape or they are overly soft and "give way" beneath you, creating a hammock like effect. The unique body molding qualities of memory foam allow your bed to conform to your body's shape, creating a cradling effect. Memory foam is an amazing material, and for years, it dominated the bedding industry because of it's body contouring and squishy, reactive feel.
Memory foam is a material that molds to the body, offering support and pressure relief where needed, and while popular for the last twenty years or so, is being eclipsed and overshadowed by beds that add other layers along with memory foam to further enhance benefits.
Developed initially for the space industry, the unique feel and comfort of memory foam is unlike any other material used in the bedding industry. Memory foam has taken off in the bedding industry over the last 20 years or so, for a simple reason – it’s comfortable, and it delivers pressure point relief and pocket filling support. There just isn't any other material that reduces pressure like memory foam. People trying memory foam often report sleeping better, get relief from pain, and experience less tossing and turning.
In the last 4-5 years though, materials like natural latex, gel foams, and highly specialized polyurethane foam made with copper, graphite and other exotic materials have become a hugely popular choice for folks looking for excellent back support with immediate spring back, as an alternative to the embracing, nest like feel of memory foam. But, the statistics don't lie...
In A study Of Over 18,000 Mattress Reviews Of All Different Types, Memory Foam Mattresses Had The Highest Overall Rating For Comfort!
Memory foam was originally developed for use by NASA engineers, to help pilots and astronauts absorb the shock of g-forces and vibrations. Ultimately, someone in the bedding industry picked up a piece of it, squished and squeezed it, and thought how perfect it would be to sleep on - turns out, they were right.
That “melting” sensation observed with memory foam is created by the way the ingredients are poured and then heated with various polymers to create the cellular configuration which gives it that unique, cradling, melted in, pressure relieving quality.
But, based on what we have learned, one problem is that a mattress built with primarily memory foam often sleeps hot, because the density of the foam causes it to collect heat, and it also can be difficult to move or transfer in and out of memory foam, often waking people up. Friends of mine who have sold memory foam beds will often say that a common reason for customers returning their memory foam mattress is that they felt “stuck or trapped” in the mattress, though they agreed it was excellent at managing pressure points. The other overwhelming complaint was that the mattresses sleep excessively hot, because memory foam is very dense, and tends to collect heat.
Despite these issues, memory foam is still highly popular, and there are a few larger companies that offer a stellar assortment of models, but as time has gone on, and because of the popularity of hybrid mattresses that contain a combination of two different kinds of foam, or even more, these companies have developed new, cutting edge beds that take advantage of the features and benefits of a combination of these amazing ingredients.
One of the key considerations when buying a memory foam mattress is understanding the basic construction involved, since durability and lifespan of these kinds of beds isn't as dependent upon the memory foam layers which are typically located at the top of the bed, and the supportive substrate foam layers are at the bottom. The underlying supportive "base layers" are typically made using a more resilient polyurethane foam, generally considered highly reliable, even over a long life cycle. I happen to own a Tempur-Pedic memory foam mattress that I have had for over ten years. It still feels fantastic and has not sunk or developed indentations. But what about understanding the different densities and qualities of the materials used in creating a long lasting, really comfortable memory foam mattress?
On my last few trips to bigger retailers, and watching what’s going on in the internet world with mattresses being sold everywhere by hundreds of online stores as well, I began to clearly observe a new phenomenon.
Mattresses made using a combination of 4lb. density memory foam and natural latex vs. other foams by themselves, were just more comfortable, and even the sales people I spoke with say they agree, because it means lower returns and additional benefits to the customer (pressure point reduction, better weight distribution, and a nice cushy, softer yet uplifting ride, thanks to the latex).
Yes, even the big retailers who innovated mattresses made using all memory foam, some costing up to $6,000, are reinventing mattresses by combining their memory foam with lots of other ingredients, from springs, to latex, to their own splashy, flashy specialty foam layers.
Remember, most of it is filler material, designed to absorb their enormous overhead like rent, payroll, huge chunks paid to middlemen, distributors, and insane commissions to sales people (not that the guy on the floor doesn’t deserve it).
Whatever you buy, if you started out thinking memory foam, just be suspicious of the price. The bigger the brand name, typically the higher the price. Shopping will take some time anyway, as there are hundreds of both memory foam mattresses and memory foam hybrids, both on the web, and in retail stores. Keep in mind that as time has gone on, prices have become very competitive, so you can pretty much find a good deal on many sites.
Memory foam is often incorporated into many hybrid mattresses out there, which makes it more confusing to buy a legitimate memory foam mattress vs. a hybrid, like Casper, Loom and Leaf, Purple, Tuft&Needle, Leesa, and others, which also have other ingredients added into their recipes. This makes it harder to buy a mattress which focuses on pressure point relief exclusively, and is the reason we created a section our recommended dealers page, under the memory foam listings, to separate these options from the hybrid beds. Memory foam will offer the following benefits that hybrid mattresses will sometimes be lacking:
- Get the pressure relieving benefit of memory foam
- Get the buoyant, uplifting feel of pure latex- no sinking in
- Excellent for side, back, and belly sleepers
- No bottoming out, no trapped feeling
- Anti-microbial benefit of latex, anti dust mite
- Generally not as expensive as all memory foam mattresses
General Rule: Look For Smaller Stores, A Strong BBB Rating, Lots Of genuine reviews, at least a 90 day trial period, and a solid warranty with at least a 10 year free replacement component.
I recommend finding a smaller, boutique style store online to buy from- You will get a really good deal likely because you are not paying for all of the overhead I mentioned. In fact, these online dealers keep things simple and often ship factory direct, saving you hundreds, and you’re probably getting the best possible product, since they are competing with the big boys, who are often forced to use less costly ingredients to save money, as I mentioned.
I also seriously scrutinize the sellers return policy. If it is a long return period, and they really do seem to back it up, then you’re probably both buying a good, well tested product with lots of happy customers (or they wouldn’t be in business), and they are trying to get you to take the leap of faith in an honest fashion.
Make sure any company you are considering has a BBB logo on their site- I say it should be at least an A- rating, because things happen, and as long as you can click on the link and see that the company resolves their issues, that is a good thing. But any company that has a B+ or better has earned it-that much is certain.
Also, reviews are always a good thing, though I am wary and more skeptical of reviews on memory foam mattresses, just because everybody and their brother sells them. Since Hybrid memory foam mattresses are all the rage right now, they are very popular..the only downside is that these mattresses are new, some less than five years old and you may not find tons of reviews on them - but the individual components used in a memory foam and pure latex mattresses, are well reviewed and studied. Also, the mattresses out there in the field have probably not been battle tested for compression and mashing as long as more established memory foam companies have been.
Be careful in general about reviews though,-many of them are cherry picked, or flat out fake- if you are going to rely on them, make sure they are third party reviews, through Power Reviews or a similar engine..you can see them on a seller’s site, but the site providing the review feed should be a separate entity that you can click on and check out.
One more big point- remember that the warranty on any mattress, whether it’s 10 years, 25, even a lifetime, is only as good as the length of time a company is in business. The longer a company has been around, the more likely they will be there in the future.
It’s What’s Underneath That Really Adds To Lifespan And Durability
One key consideration though, is the quality of the synthetic high density foams used underneath, which can broadly range in quality from outright utility grade foams which aren’t even bedding grade material, (like foam you would use to pack household goods in a move) to extremely high quality foam layers that are especially designed to be used for support layers in mattresses.
Almost all of them are made using petroleum based products, which may be a concern for some folks. There are new materials and foams out there though that are manufactured without a lot of the toxic ingredients used in the past. Still, though, many people are concerned about synthetic materials being used in their beds..
memory foam is really polyurethane foam...What are the risks of VOC exposure, and Off-Gassing?
You might read a lot about synthetic foams, which are made using petroleum products, “off-gassing” as they age. Sometimes, retailers selling all natural beds like pure latex, for example, will create scare tactics to steer you away from these "chemical beds". Off-gassing refers to a phenomenon of chemicals breaking down and leeching into the air, which some have attributed to allergic reactions, breathing issues and toxin buildup. Memory foam and all polyurethane-containing and otherwise manufactured products can have a “new” odor, which is typically harmless and fades over the first few weeks. A good piece of advice, even though these mattresses can be cumbersome, if you can get it outside and park it across a table, some chairs, or other surface on a sunny day, atmospheric ozone will chip away at the smell very fast. I've done that with any new mattress I've ever purchased. One good bright afternoon usually does the trick.
The term VOCs is an acronym for volatile organic compounds. VOCs are unstable and break down or at room temperature, releasing odors as they do. We all know the smell of VOC's if you have ever smelled fresh paint, new cars, new furniture, or even a can of solvent or WD40, for example.
Alone, their impact ranges from safe to toxic according to readily available Material Safety Data Sheets you can access with most products. Several are no more significant than an odor, and even humans and plants release types of VOCs as a part of biological processes.
However, some sources (some of which can be in memory foam like toluene, benzene and formaldehyde) have been associated with respiratory irritation, throat irritation, forgetfulness, feeling dizzy or developing a headache, and repeated exposure can lead to sensitization or allergic reactions (this is typically associated with workplace exposure however, according to the EPA). However, in the finished product, say a memory foam mattress combined with a polyurethane foam, the effect is going to be short lived, and will clear within weeks, even days if you sue my little trick..
Typically, VOC hazards are higher in the raw materials used to create products like foams than in the finished product itself. As with memory foam, once the chemical components are combined into a finished product, the VOC release is minimized. Unreacted polymers and other components like glues and fire retardants can pose lingering odors and strong scents as well, though. I was suggest one very important thing. In the mattress industry, there are two types of adhesive typically used. the most common type is a quick set VOC and formaledehyde adhesives (used to glue adjacent layers of foam together), which is fast drying and convenient for large scale production operations, and there is a water based, non-toxic adhesive that several companies use, especially those selling natural latex beds, called Simalfa, which is completely safe and non-toxic, even labelled for infant bedding. You can ask for it by name when you are researching your mattress options. It takes some expertise to use it, it takes a day or so to dry rather than 10 minutes, but it is much safer. People sensitive to smells or VOC's in general would be well advised to buy a mattress with Simalfa adhesive used in production.
How Do You Know if You’ll Be Affected?
Out of the many consumers who have bought memory foam beds, a very small portion seem to experience allergic-type reactions. There are some reports online of people experiencing nose, throat or eye irritation, asthma irritation, or nausea which they attribute to mattress odors. These reviews are in the minority compared to the hundreds of thousands who have purchased memory foam mattresses without incident over the past 25 years. According to Sleep Like The Dead’s research, a reliable resource for accurate statistical analysis of everything bedding, odors cause less than 2% of people overall to return their mattresses.
Although different brands can vary on odor, beware if a company is trying to sell you “no VOC or VOC free” memory foam, since it actually doesn't exist. A memory foam can be “low VOC” or “free of toxic VOCs”, but as we’ve mentioned before, almost every organic product has at least some minimal off gassing that is essentially harmless, but may frighten you at first.
But, amazingly, there are synthetic foam materials that are made using a proprietary sequence of steps to remove many harmful materials from the process. One example of this material is a specialized foam that is known as Certi-Pur® foam. This kind of foam is free of harmful ingredients typically found in petroleum based foams, like PBDE’s (poly-brominated di-ethyl ethers) which are toxic and achieved notoriety for contributing to ozone layer depletion, as well as formaldehyde, volatile organic compounds, heavy metals, and other toxins, all of which continue to off-gas over long periods of time.
It is available in many densities and degrees of firmness, so that it can be properly calibrated with the top layers of the mattress to deliver the highest level of comfort and support. Here’s a link to the consumer page for Certi-Pur®, which you can check out after reading my article.
what GIVES MEMORY FOAM ITS "MEMORY"
To give a piece of foam the sensation of memory, the process begins with a synthetic polyurethane foam material and by adding a specialized formulation which increases the weight or density to the foam. With the addition of these chemicals, a non-toxic foam material is created. Some like to refer to this as “viscoelastic memory foam.” However, there are many features along the way that will help determine what type of memory foam you may prefer. To understand exactly what differences are found in each final product, you first have to start with understanding the nature of memory foam and the many options available.
With the success of Tempur-Pedic® mattresses in the USA, other foam manufacturers began to develop their own memory foam material to offer to mattress, upholstering and specialty products companies the ability to allow consumers to have a variety of options and price levels to choose from.
understanding memory foam and how it is rated and graded
For a material to be visco-elastic, it has to be temperature sensitive and have an ability to rebound fairly quickly and return to its normal shape. When you try out a memory foam mattress, you'll immediately notice a "melting in" sensation, which increases as more body heat is applied. Memory foam is graded by its responsive and viscous nature and its durability by categorizing it in the following grading system:
1. Weight (Density in pounds per square foot):
The weight of a foam is determined by the amount of ingredients used in the composition of the urethane foam. The more chemicals, the higher the density and the more squishy and responsive it will become. The density will not grade the firmness of the material, as that is quantified by giving it an ILD rating. Many memory foam mattresses use a 4 and 5-lb. density, but some use as low as 1, 2 and 3-lb. densities. Typically though, a good quality memory foam mattress will be composed of a 4-5 lb. density layer or layers, above a firmer substrate polyurethane, non visco-elastic foam, for support.
2. ILD Rating (Indentation Load Deflection):
The ILD rating is going to tell you how hard or soft a material is. Indentation Load Deflection is a measurement in firmness level. The higher the number, the more firm it is and vice versa for lower numbers. When measuring ILD, there have been standards put in place that the industry uses to ensure you have a clear idea of just what the numbers represent. To test, a foam sample of material measuring 15 inches x 15 inches x 4 inches is used. A 50 square inch circular indenter, which applies the pressure, is used to compress the material a total of 25 percent of its thickness.
This measures the foam’s "springiness" by determining the percent rebound of a steel ball dropped from a height of 36″. The term “H.R” (highly resilient) foam refers to a highly resilient foam that will give a very high “ball rebound” or ball bounce, reading. In general, the higher the resiliency, the better and more durable the foam will be with compression forces. However, with viscoelastic memory foam, less resilience indicates a better force dampening. This is due to less rebound pressure fighting the force of your body as it sinks into the mattress. Very high quality memory foam mattresses combine lower high resilient layer(s) with memory foam on the surface, so you get the pressure point reduction, while retaining the extra support below.
4. Tensile Strength:
This indicates the extent to which foam can be stretched, measured in pounds per square inch, and how much elongation in terms of percent of stretch before rupture. This value has little relevance to memory foam mattresses because they are not usually stretched, and will become compressed only when slept on. However, in hybrid mattresses, where the memory foam is adjacent to a material of different density like latex or gel foam, or even softer foams, I have seen splitting and cracking with inferior memory foam, usually below 4 lb. density ratings. With memory foam, get the 4lb or 5lb stuff for sure.
what is that smell that seems to come along with a new memory foam bed? is it dangerous?
While memory foam manufactured in the U.S. does not contain toxic ingredients such as formaldehyde or PBDE (poly-brominated diphenyl ether), it can have somewhat of a new foam or new car type of smell that can stay for a couple of days to a couple of weeks, depending on the foam manufacturer. While this smell does not seem to trigger allergies, it can initially be a bother for people who have sensitivity to smells. It is considered harmless, and is more of a nuisance issue. If you do experience this, however, here are some tips to help the smell go away more quickly:
• Air out the room and wash the sheets after the first couple of nights sleeping on the mattress.
• Sometimes a dish of vinegar on the night stand can help nullify the odors.
• An ozonator machine will rectify the situation very quickly. Even better, if you can do it, set the mattress outside on a bright sunny day, and let some atmospheric ozone chip away at it for 4-6 hours. I have done this with several memory foam mattresses that I have owned.
what about organic or so-called "green memory foam"?
One new trend in all bedding is to speak about organic memory foam or green memory foam. While there are ways to make memory foam more environmentally friendly (Biogreen® Memory Foam is one such example), for memory foam to have the same type of visco-elastic feel and support as the original NASA developed formulation it cannot be organic or soy-based (usually 5-10 % soy can be added to memory foam), nor can it be all-natural. However, the memory foam made in the United States has been shown to be safe and non-toxic, and some manufacturers have gone one step further to reduce or eliminate V.O.C. off-gassing odors and other borderline chemical additives.
does gel memory foam sleep cooler than regular memory foam?
One of the chief complaints about memory foam is that it can be hot for some users. This is simply due to the very dense nature of memory foam and, consequently, it may have a tendency to collect heat rather than passively ventilate it away from the mattress. This prompted various ideas of how to keep a memory foam mattress cooler, including using a gel infusion with either beads or mixed right into the memory foam itself.
The problem with gel is that it is a conductive substance that responds to the environment around it. This makes it great for those who want to temporarily cool off when getting into bed, but users should know that the coolness won’t last throughout the night, since your body’s heat will warm up the gel more than it would other less conductive substances. Also, gel infusion has not been around long enough to prove its durability and, in fact, it is a well know fact that gel beads easily separate from the memory foam. The key to enjoying a memory foam or memory foam hybrid mattress is the outer covering or ticking. It should be a breathable fabric, like organic cotton or bamboo, two materials that act as insulators and will passively move heat away from the mattress surface.
what should i place my memory foam or memory foam hybrid mattress on as a foundation?
A good memory foam mattress will not need a box spring underneath it to make the mattress feel fantastic. You can order a platform base to increase the height of the bed, but remember that this mattress should feel good if it was placed on an even, concrete surface. A good way to test the surface of a box spring or box foundation is to sit or even stand on various areas and see if it compresses underneath you. If you have an existing foundation that is weak, you can easily place two cut 3/4" to 1" thick plywood sheets over it to give it the necessary support. An adjustable base is also a great option for a memory foam mattress, too, as the surface is resilient and supportive, and memory foam has a high degree of flexibility, making it ideal for sitting up, elevating legs, etc.
coil mattresses vs. memory foam or memory foam hybrid mattresses
While a spring mattress was the standard for many decades, foam mattresses are becoming more and more popular due to their unsurpassed comfort and overall body support. While spring mattresses can feel nice to sit or lie on, they will not offer anywhere close to the body contouring, and therefore spinal support, that memory or latex foam can offer. There is always fiber and some type of foam over the springs, but these coils will actually cause a trampoline effect and bend inward when pressure is applied without conforming to the specific bumps and curves of the body. While foam can shrink over time, springs can bend and lose their shape over time. Therefore, an old foam bed will likely feel better and offer better support than an old spring mattress.
memory foam vs. latex foam
Latex foam has a higher elasticity or resiliency than memory foam. The result is that latex will feel more springy, and memory foam will feel more solid. Therefore, memory foam will not push back up against your body upon pressure being applied to it. Many mattress companies are using both of these two materials to blend the perfect mattress combination, creating the ultimate hybrid mattress. I think that this is the wave of the future as it combines the two most unique materials available in the industry, and each compliments the other. Memory foam helps distribute pressure, but the latex if underneath, will still keep you afloat and buoyant. With the latex on top, you can still remain on top of the mattress without that sinking sensation, and get the pressure relief you need from the memory foam underneath. A hybrid mattress with the two layers placed so you can swap them out is probably the ideal recipe.
Rare allergies to latex can be triggered, but usually upon skin contact, and usually not with the natural and synthetic latex blends like Talalay. This is because the proteins thought to trigger these rare allergies are usually washed away in the Talalay latex foam produced in the U.S. Talalay latex is more supple than Dunlop latex. It is more expensive and is composed of synthetic and natural latex. Because there are no chemicals used in latex composition, it is the ILD only that determines the feel of this product.
MEMORY FOAM VS. DIGITAL AIR BEDS
Digital air mattresses have also become progressively more popular due to the interesting concept of being able to change the feel of your mattress with a control. With many air mattresses, you can change both sides of the bed to different firmnesses by moving air in and out of air chambers.
Also, you will not get the same contouring of the body that you can get with memory foam, as air beds will not make an imprint of your body. In fact, it is more similar to a spring bed in that it may create a trampoline effect and bend inward when pressure is applied without conforming to the specific bumps and curves of the body. This is because air displaces to the sides of the body, leaving the middle with less support.
Memory and latex foam are the only substances that can accomplish a contouring of the body without losing support. There are newer technologies in airbeds that offer memory foam in the top layer system, but without the ability to change the pressure of the middle region independently of the shoulder and leg sections of the mattress, a loss of middle support will occur with any reduction in air pressure. Also, many airbeds will not blend well with the memory foam due to a non-flexible chamber system.
is memory foam the best ingredient for those tired and aching joints and muscles?
When you take into consideration the amount of pressure you place on your shoulder and hips if you are a side sleeper, neck if you are a stomach sleeper, or lower back and sacrum if you are a back sleeper, you will realize that visco-elastic pressure-sensitive foam will offer you the best chance for reducing the overall pressure placed on your joints by contouring them without pushing back against them. With latex added to a memory foam mattress, it can offer a bit more spring against the concavities like the small of your back or sides, while not losing the ability to contour and displace pressure points.
The memory foam mattress category is rapidly evolving these days. Components like natural latex, gel foams, and more breathable fiber layers nestled between layers of foam, are becoming hugely popular for more luxurious support and a softer, more yielding feel that reduces pressure and relieves pain, without the sinking sensation and “wet sand” feel that a lot of people who buy an all memory foam mattress complain about.
Latex, for example, is typically an all natural material made from the sap of the rubber tree, and is collected, cleaned, and poured into large mattress shaped molds, and solidified. In fact, natural latex mattresses have been around for decades, since the 60’s, and were hugely popular with Sears and other companies because they were fairly inexpensive.
It is an ideal material for providing uplifting, buoyant support, making turning easier, keeping you asleep, and it is luxuriously “spongy” and comfortable- with no sinking feeling at all. It’s not the best at pressure relief, but- what if it were combined with memory foam?
At one time, the comfort of memory foam had been shown, by analyzing thousands of online reviews, to far exceed the standard innerspring bed, and that of any other category of mattress- but - that is rapidly changing, as the landscape of mattress options has quickly evolved, especially as Hybrid mattresses, beds that combine two or more beneficial ingredients, rapidly eclipse memory foam when used by itself, as well as almost every other category of mattress.
But are other mattresses, like latex, and gel foams, which are gaining intense popularity as they rapidly fill up floor space in mattress stores, the better option than an all memory foam mattress? Should memory foam be combined with other ingredients to enhance its pressure relieving feel?
The Hunt For The Perfect Mattress Seems Confusing, Right?
Do a Google search for “best mattress” and your brain goes into immediate overload with names like Casper, Habitat Furnishings, Purple, Leesa, Zenhaven, Simmons, Saatva, Tuft And Needle, Lull, Loom And Leaf, and on and on. All of these companies have worked hard to carve out a niche using specialized synthetic foams, latex, and memory foam to orchestrate their version of the perfect mattress. All of these companies have great web sites, most have solid reviews from third party sources, but how can you be sure you’re getting what you paid for? And if you’re getting quality ingredients for your money?
Shopping for mattresses these days is worse than shopping for a used car. Every mattress store or site will tell you that their bed is the most amazing thing ever, and you might overlook the fact that they are using lots of ingredients which are given fancy names like “Dream Foam”, ‘Plushfoam”, or “Ultra Foam”.
The fact is that most of these foam layers are often cheap, synthetic foam- the same kind of foam you’d use for a boat seat cushion, to wrap your kitchenware with during a move, or even install under your new carpet.
They are often materials that, while they sound really impressive, are not well thought out, and are used simply as filler material. Worst case scenario, on top of the mattress, you might find a layer of low quality memory foam or synthetic latex that is lower density and collapses easily over time, but the price seems right- usually right around $700-800, or maybe even a tad less.
Remember this - like anything else in life, you get what you pay for. A memory foam mattress that retails for $800 needs to be filled a fair amount of inexpensive filler material to be able to leave room for even the thinnest of profit margins. Look at the sites at the top of most internet searches for “best mattress” as an example. It can cost these companies $200 to get a customer to their shopping cart. Believe me, you’re paying for it, and it’s built into the mattress cost, buried somewhere.
So, What Should I Look For If I Want The Benefits Of Memory Foam, And I Want The Bed To Be Comfortable, Cushy, Supportive, And Pain Relieving?
First off, memory foam is a perfect ingredient to a good combination, or “Hybrid” mattress that takes the best of all worlds and rolls it into one magical mattress. But, you’ve got to have the right kind of memory foam and other components, like latex and gel foam, to deliver the best results.
Gel foams generally sleep hot, as do most other synthetic “filler foams”. Be wary of web sites or stores that have layers of foam with sketchy names like “Dream Foam” or “Ultra Foam”, which is merely code for cheap filler foams that allows us to make a huge profit.
As far as memory foam hybrid mattresses are concerned, I recommend using pure natural latex as the best partner with memory foam. But, make sure you get 100% plant based latex, and not synthetic latex, which is often substituted for the good stuff. The fact is, synthetic latex behaves more like the cheaper filler foams, being harder, less responsive, and less “cushy” than botanical latex.
Another hugely popular thing about sleeping on latex is that it is naturally antimicrobial, it repels dust mites, it doesn’t off gas VOC fumes, and it simply does not break down over time. The reason it lasts virtually forever without collapsing is because it is not photo-reactive and will not turn brown and dry out, turning into crumbs, like an old couch cushion. Many poor quality foams made using polyurethane and other synthetic materials have this property, and will deteriorate over time with exposure to light.
I recommend only natural latex, since synthetic latex (called SBR, for styrene butadiene rubber, a petrochemical) does not offer the same benefits, and tends to be stiffer and less “jiggly”, not having the flexible, elastic feel of the purely botanical version.
Also, the memory foam should be what is called 4lb. density memory foam, so that it is supportive and does not bottom out easily, offering the pressure relieving qualities you want whether you are a side sleeper, or a back or belly sleeper. Most companies out there are doing everything they can to pitch you a real pretty mattress with a cool looking covering and fancy box, while skimping on the ingredients, and instead using inferior 3lb. density or less, which will eventually compress and mash down, even split and crack, over time.
A memory foam mattress can deliver a level of comfort and pressure point relief unlike any other bed. Because of its unique "melting" and wrapping up around you sensation, it is a very nest-like and wonderful sensation. People who sleep cool often find memory foam satsifying since it tends to sleep warmer. Hot sleepers can have issues with the temperature sensitive nature of the foam, but using mattress pads and other cooling fibers can provide great relief.