What is a Memory Foam Mattress? All You Need To Know

by Max S
What Is A Memory Foam Mattress

You’ve probably heard of memory foam mattresses; they’re plastered everywhere, from TV adverts to shop windows. But what is a memory foam mattress? How do they compare to other mattress types?

Not knowing the different qualities of a mattress before buying can be a massive nuisance, from returning it to forking out for a new mattress in the meantime. It’s an unnecessary waste of time and drains your wallet for no good reason. Especially when all the information is out there before you buy!

Quick Read: Spring vs Foam Mattresses

And if you’re buying a memory foam mattress you’ll want to take loads of factors into account:

  • Are you sleeping with a partner?
  • What position sleeper are you?
  • Are you a hot sleeper?
  • Do you suffer from allergies?
  • Do you suffer from common pressure point pain?

Let’s not waste a minute more and get into how memory foam mattresses work, who they’re good for and who they’re not and how they can help you achieve a good night’s sleep.

How does memory foam work?

Did you know? NASA first developed memory foam in the mid-1960s to help astronauts deal with the high pressure they endured when leaving and reentering the Earth’s atmosphere. People then discovered memory foam’s potential for application in other products, and now used in mattresses, pillows, and mattress toppers.

Memory foam is a viscoelastic material. What does viscoelastic mean? Let’s break it down into two – visco and elastic. “Visco” came from the word viscous, which means the resistance of a liquid to flow.

Related Read: Best Memory Foam Mattress UK

Think of it as water being less viscous versus honey being more viscous. “Elastic” means that an object can be deformed and return to its original shape, just like rubber. Memory foam, being a viscoelastic material, can do this.

Memory foam’s viscosity reduces with higher temperature. Viscosity is when memory foam becomes more flexible as the temperature rises. It will feel softer after resting on them for a while since it will absorb the body’s heat.

what is a memory foam mattress with red wine glass
Motion isolation on memory foam.

You may wonder why memory foam is called “memory foam”. Once you apply pressure to the memory foam, it contours to your body curves. Once you remove the pressure, it remembers your body form for 5 to 10 seconds. It slowly returns to its shape only once pressure is released, hence the name” memory”. This phenomenon is known as hysteresis, the time lag between when the force is removed and when the memory foam returns to its original shape.

Memory foam’s remarkable ability to contour than other mattress types ensures healthy spinal alignment and even weight distribution in all sleeping positions.

Components of a Memory Foam Mattress

Memory foam mattresses have different constructions depending on the manufacturer. However, all memory foam mattresses follow a similar structure. There are three parts to this: the comfort layer, transition layer, and mattress core.

  • Comfort Layer: The uppermost section of the mattress contains the memory foam layer and is used for cushioning. Its thickness and layer count depends on the manufacturer’s design. Some designs would have two to three layers for the comfort layer and may include classic memory foam, gel-infused foam, memory foam with air channels, or latex foam.

Since a memory foam mattress can get hot whilst sleeping, new technology has allowed more permeable foams to promote airflow. There are even gel-infused foams (what is a gel mattress?) that help to keep you cool at night.

  • Transition Layer: This mattress section comprises one or more foam layers that serve as a transition between the core and comfort layers. They’re a little firmer than the foam in the comfort levels, and they aid in reducing heat away from the comfort layer by using cooler materials like permeable foams.
  • Core: This is the base of the mattress and is usually made out of significantly firmer foam and is the thickest layer by far. It gives stability and support to the mattress.

Related Read: How To Keep Cool On A Memory Foam Mattress?

Types of Memory Foam

3 main types of memory foam have different advantages for different sleeper types:

  • Traditional

Traditional memory foam is what most people probably think of when memory foam is mentioned. After all, it was the original memory foam first introduced to the market. It has a dense structure that was initially designed by NASA. This classic memory foam is designed to contour the body. However, the only downside is that it tends to trap body heat because of its dense structure.

A traditional memory foam mattress has a denser structure than an open-cell foam but is less dense than a gel-infused foam. The other two varieties of memory foam, open-cell and gel memory foam, were designed to address the heat retention problem of the traditional memory foam.

Considering the properties of traditional memory foam, it is recommended for

  • cold sleepers
  • stomach sleepers
  • back sleepers
  • people weighing more than 100 kg
  • Open-cell

As mentioned earlier, open-cell memory foam was designed because of the heat retention with the traditional memory foam. They are both made with the same polyurethane components, but their main difference is the internal structure. Internal pockets or “open cells” in open-cell memory foam mattresses allow more airflow within the mattress than traditional memory foam. The ventilation would help dissipate heat that is absorbed by the memory foam.

Because of the internal pockets, open-cell memory foam is less dense than traditional memory foam. And because of the lesser density, the firmness of the open-cell mattress is also decreased.

Considering the properties of the open-cell memory foam, it is recommended for

  • hot sleepers
  • side sleepers
  • people weighing less than 100 kg
  • Gel-infused

Gels are injected into the foam by pumping gel-based microbeads. These microbeads create pockets similar to those found in open-cell mattresses. These gels are “phase-changing” materials. They actively absorb and release heat from your body, rather than merely allowing air to pass through the mattress like an open-cell mattress.

Because the voids in the mattress are mostly filled with gel, gel-infused memory foam is the densest of all three types. It would also feel the most firm because of the density.

Considering the properties of the gel-infused memory foam, it is recommended for

  • hot sleepers
  • stomach sleepers
  • back sleepers
  • people weighing more than 100 kg

Memory Foam Density

Memory foam is available in different densities, affecting the firmness and cost. Foam density is measured as kilograms per cubic meter. Sometimes it’s just kilograms.

You can refer to the table below for a general reference on the different foam densities.

Foam Density



Recommended Sleeper Weight

Recommended Sleeping Position



40 kg

Lighter body; Less than 100 kg

Side sleeper


Medium firm

60 kg

Average body; Less than 100 kg

Side sleeper, back sleeper, stomach sleeper



80 kg

Heavier body; More than 100 kg

Back sleeper, stomach sleeper

The higher the density is, the firmer and more supportive the mattress is. High-density mattresses can support weights of more than 100 kg and give enough support for stomach sleepers without sinking deeply into the mattress.

In terms of cost, higher densities would come at a higher price because of the materials used. The durability of a mattress also depends on the density. Low-density mattresses lose their form and flexibility faster, whereas high-density mattresses can better resist compressions over time. Higher memory foam densities are beneficial for heavier people of 200+ lbs and people with back and joint problems.

Most people prefer medium density foam because it is suitable for all sleeping positions and less expensive than the high-density foam. If you’re wondering what density is best for you, we recommend testing it out personally at a mattress store. The firmness is always subjective to a person’s weight, and mattress quality differs from one manufacturer to another.

Benefits of Memory Foam Mattress

Because of the numerous benefits that memory foam mattresses give, they are a popular choice. These benefits include:

Conforms to Body

Memory foam responds to body heat and pressure by adapting to the shape of your body. This is ideal for various sleeping positions because it cradles your body’s natural curves and relieves pressure points. When sleeping, it aligns the body’s neck, spine, and hips since it adjusts to your exact sleeping posture. When the mattress does not conform to the body, the spine will not be in alignment and will cause back pain later on. People suffering from back pain and joint pain will benefit from using a memory foam mattress.

According to recent research and studies, people sleep better on a medium-firm, self-adjusting mattress like memory foam. This is ideal for increasing sleep comfort, quality, and spinal alignment.

Motion Isolation

As NASA originally developed memory foam to reduce motion transfer and absorb shock transfer, it provides excellent motion isolation for you as a sleeper. The dense structure of the memory foam is the reason for the motion isolation because of the compact cells that serve as shock-absorbers.

Because memory foam cradles the sleeping individual, it doesn’t disrupt the rest of the mattress if you move. This is perfect for couples sharing a bed, especially if one is constantly tossing and turning at night.


Unlike a traditional spring mattress where you may hear squeaks, a memory foam mattress is known for having noise reduction qualities even when jumping on the bed. This quality is crucial for couples who share a bed and don’t want to disturb their partners while getting out of bed.

Hypoallergenic and Dust-mite Resistant

Mattresses used to be created from materials like feathers and wool, which may be a nightmare for someone with allergies. Thankfully, memory foam is hypoallergenic.

The density levels of memory foam make it hard or almost impossible for dust mites and other allergens to infiltrate the foam.

Works with Adjustable Base Beds

Adjustable beds are recent innovations in the bedding industry that allow you to raise your bed in reclining positions. Unlike spring mattresses with a metal frame, memory foam mattresses have more flexible bases that can be used for adjustable beds.

Disadvantages of Memory Foam Mattress

Although there are great benefits, there are drawbacks. Memory foam isn’t for everybody. Below are some of memory foam’s disadvantages, as reported by some users.

Absorbs and Retains Heat

Since memory foam uses your body’s heat to adjust to its natural shape, there is a tendency for too much heat to be trapped inside the mattress. The dense structure of the memory foam also makes it hard for air ventilation.

This can lead to overheating on hot summer nights. So, if you’re a hot sleeper, you’ll probably suffer from sleeping too hot and excessive sweating.

Tip: A mattress cover, or a mattress topper, is one way to resolve this issue. Cool materials like cotton and wool are helpful in this case.

Initial Odour

Due to the chemicals used in the manufacturing process, memory foam mattresses come with an initial odour after opening them. The foam itself, resin, and adhesives produce these gasses known as volatile organic compounds or VOCs. Flame retardants applied on the mattress to meet the government-mandated standards can also produce VOCs or off-gassing.

But don’t worry. It’ll pass for a few days if you keep the mattress in a well-ventilated room. Regulatory agencies like EU Regulation also guarantee that off-gassing from mattress manufacturers is kept to safe levels.


Water or any liquid can harm memory foam by deteriorating the foam and shortening the memory foam mattress’s lifespan. If you reside in a humid environment or have a young child or pet prone to spills or accidents, read our tip below. This also makes it tough to clean a memory foam mattress.

Tip: If you’re going with memory foam, using a waterproof mattress protector or cover is good. They protect your mattress from any liquids that could potentially compromise the quality.


All these great benefits come with a cost. Compared to regular innerspring or foam mattresses, memory foam is generally more expensive. Especially if you consider buying a high-density memory foam. For example, Emma memory foam king mattress is priced at around £440. In comparison, John Lewis & Partners spring king mattress is priced at about £210.

How long does a memory foam mattress last?

A high-quality memory foam mattress can last up to 10 years. However, they can last longer if properly cared for. What factors can affect the lifespan of your memory foam mattress?

Manner of Use

Sagging of foam mattresses occurs naturally over time due to the frequency of use and the sleeper’s weight. The more the mattress bears weight, the faster it deteriorates because of the compression of the foam.


One of the properties that make memory foam mattresses hypoallergenic is the density of the foam. However, this also makes it much more difficult to maintain and clean your memory foam mattress. Regular cleaning of your memory foam mattress can help prolong its lifespan, and that includes:

  • changing the bedding
  • vacuuming dust and debris
  • wiping spilt liquids immediately

Rotating the memory foam mattress once a month is also a good practice and a recommendation by some manufacturers. Memory foam begins to sag and soften over time, so to balance this wear and tear, you can flip the mattress or rotate it from head to toe.

Check with the manufacturer’s care instructions if your mattress needs rotation or flipping.

Can a memory foam mattress cause back pain?

Back pain may be caused by your sleeping position and how your spine is aligned during sleep. A memory foam mattress is often recommended for back pain because of its body contouring capability, allowing for greater spinal alignment.

However, if you think your memory foam mattress is not doing its job to align your back, it can be of the following two factors:

The mattress is too firm or soft for your weight.

If your memory foam is too soft for your weight, you will sink too deep into the mattress. Your spine won’t be in alignment and may cause back pain. On the other hand, if your memory foam is too firm, it would cause pressure on your back and cause back pain.

It is crucial to test out the mattress you’re buying first. As a rough guide, below is a guideline for choosing firmness depending on your weight.

  • Soft mattress: Sleepers of less than 70 kg (150 lbs)
  • Medium-firm mattress: Sleepers of 70 to 100 kg (150 to 230 lbs)
  • Firm mattress: Sleepers of more than 100 kg (230 lbs)

The mattress firmness is not compatible with your sleeping position.

Since memory foam mattresses conform well to body curves, side and combo sleepers will be comfortable sleeping on soft foams. The shoulders and hips can sink as far as they need to, while the flank and thighs are sufficiently supported to perfectly align the spine.

On the other hand, stomach and back sleepers would benefit from medium-firm to firm mattresses instead. This will ensure that they won’t sink into the mattress, and their spine will be misaligned during sleep.


Overall, memory foam mattresses are an excellent option for a new mattress. They are cost-effective and long-lasting, ensuring that you get your money’s worth and providing additional health advantages to improve your sleep quality.


National Aeronautics and Space Administration

Radwan A, Fess P, James D, Murphy J, Myers J, Rooney M, Taylor J, Torii A. Effect of different mattress designs on promoting sleep quality, pain reduction, and spinal alignment in adults with or without back pain; systematic review of controlled trials. Sleep Health. 2015 Dec;1(4):257-267. doi: 10.1016/j.sleh.2015.08.001. Epub 2015 Oct 19. PMID: 29073401. https://pubmed.ncbi.nlm.nih.gov/29073401/

Photo of author


Max S

Chief Editor here at The Sleep Checklist. Suffered from a seemingly infinite knot in my thoracic area (between the spine and shoulder blade) due to my lifelong side sleeping habits. With my girlfriend, we look to provide the most relevant and best mattress advice.