What Is Memory Foam?

Written by: Andjela Kastratovic
Updated: 06/09/2023

Memory foam is hailed as one of the most comfortable mattress materials, but why is that? What is memory foam made of? And what makes it so comfortable?

Memory foam could be the perfect choice for you, but it could also be something you should avoid. 

Let’s talk about memory foam.  

What Is Memory Foam Made Of?

In 1966, NASA created memory foam for the first time in space shuttle construction to make astronauts’ space travel safer and more comfortable. But this material became something much more in our everyday lives. 

The main component of memory foam is a highly versatile plastic polymer called polyurethane. It’s not limited to memory foam mattresses – you can find this polymer in sofas, spray foam, insulation, and other stuff around your home. 

However, memory foam is a polyurethane foam created by adding different compounds and additives to polyurethane. Two things make it stand out – viscosity and elasticity. 

Viscosity means that a material moves and changes shape slowly when applying pressure. An excellent example of viscosity is honey. On the other hand, elasticity refers to the material’s ability to stretch, contort, and bounce back to its initial shape when the pressure’s gone. 

This is why we call memory foam viscoelastic foam. This viscoelastic polyurethane foam conforms to the body but turns back to its original shape when you’re not applying pressure on it. 

But not all memory foams are the same. Different manufacturers add different compounds to the polyurethane foam, changing the levels of viscoelasticity and comfort. You just need to find the right memory foam mattress for you.

How Does Memory Foam Work?

This viscoelastic foam is designed to respond to pressure by gradually molding to it and to evenly distribute body weight. It’s also resilient enough to bounce back to its original shape. 

The way that memory foam responds to force depends on the force itself. If something hits it fast and hard, memory foam will react slowly, absorbing the impact. This is precisely why NASA created it. 

And it takes about 5 to 10 seconds to revert to its original shape. This phenomenon, called hysteresis, also creates a more comfortable sleeping environment by removing some of the pressure. 

How the memory foam responds to your body is also significantly related to heat. The more your body heat increases, the more flexible the sleeping surface will get. This is why the longer you lie down on a memory foam mattress, the more it’ll feel like it’s responding to your body shape. 

Memory Foam Mattress Construction

While there are variations in construction, most memory foam mattresses follow a basic template consisting of three essential foam layers.

  • The comfort layer – located at the top of the mattress, provides cushioning and contouring with varying firmness levels. This layer is usually made with more breathable foams. 
  • Transition layer – the layers between the support and comfort layers use transition foam to help with comfort, generally adding more pressure relief, breathability, or motion isolation in memory foam beds.
  • Support layer – the support layer in a memory foam mattress is usually made from polyfoam, a high-density foam more suitable for support. This layer has steel coils if it’s a memory foam hybrid mattress. 

Memory Foam Mattress Types

There are a couple of types of memory foam mattresses you should know about. Manufacturers create new foams all the time to make their products more comfortable for you. 

They’re all contouring, but there are a couple of things that set them apart from each other and maybe even make them slightly better. 

But before we get to the newer versions, let’s start with the basics. 

Traditional Memory Foam

Traditional memory foam mattresses are designed to mold your body, providing a comforting hug as you sleep. They’re very dense and have a closed-cell structure. 

However, one drawback of a traditional memory foam mattress is its tendency to retain heat, which can make the sleeping surface uncomfortably warm. 

To tackle this issue, manufacturers have developed other types of memory foam.

Open-Cell Memory Foam 

Because the closed-cell construction of traditional memory foam traps heat, manufacturers created open-cell memory foam mattresses. The open-cell structure helps combat the heat and adds a cooling effect. 

Open-cell foam has everything a traditional memory foam mattress does, but its internal structure differs. Open-cell memory foam mattresses also used to be less dense, creating problems with support, but newer technologies made them more reliable. 

Gel Memory Foam 

Gel is another way to combat heat retention in traditional memory foam mattresses. 

The gel is incorporated into the foam by pumping gel-based microbeads into it, creating pockets similar to those found in open-cell mattresses. The gel forms an excellent sleeping surface, preventing overheating. 

Gel-infused memory foam mattresses offer faster bounce-back, heat absorption, and pressure point relief, resulting in a cooler and more comfortable sleep experience.

Additionally, some types of memory foam mattresses incorporate copper, aromatherapy scents like lavender, or layers of corrugated foam for enhanced cooling and comfort.

Plant-Based Memory Foam 

There are also plant-based memory foam mattresses. These provide the same contouring and relieve pressure as traditional memory foam mattresses, but they’re also more breathable and make an excellent eco-friendly choice. 

It’s also a good idea if you’re looking for a mattress with low volatile organic compound (VOC) emissions. 

Hybrid Memory Foam

And if you need more support, hybrid memory foam mattresses are there to save the day. 

Many hybrid mattresses today combine memory foam in the comfort layer with other types of mattress construction in the support layer, such as pocket coils from an innerspring mattress or latex foam layers. This combination offers a unique blend of comfort and support for a great sleep experience.

What Does Sleeping on Memory Foam Feel Like?

It feels like sleeping on a cloud. 

Memory foam molds to your body shape, creating a supportive and pressure-relieving surface that lets your body sink without applying too much pressure to your joints. Bonus points: It’s good at motion isolation, so if you sleep with a partner, you won’t feel them tossing and turning. 

Memory foam makes you feel like you’re sinking into the mattress. However, remember that this sinking feeling isn’t for everybody and might leave some people with mobility issues feeling stuck. 

But if you’re a hot sleeper and decide to go for traditional memory foam, sleeping on this mattress might get too hot because it traps heat. 

How to Choose a Memory Foam Mattress

If you want to make sure that you also feel like sleeping on a cloud every night, you need to take a couple of things into consideration. 

Here’s what to watch out for when buying a memory foam mattress. 


No matter what it’s made of or your sleeping position, a mattress is supposed to keep your spine aligned. 

A misaligned spine doesn’t just make your sleep more uncomfortable; it also causes health issues and joint pain. 

Lucky for us, memory foam mattresses tend to have good support for most people, thanks to that support layer of firm polyfoam. 


Mattress firmness is subjective, but it’s usually described on a scale of 1 to 10, going from extra soft to extra firm. 

According to data, most people prefer a medium-firm mattress, but that might not be the case for you, as the perfect mattress firmness can depend on many things.

Memory foam mattresses can have varying degrees of firmness, but they’re usually described as softer. It generally depends on the ILD, as you’ll see next. In any case, you have plenty of options to choose from. 

Density & ILD

When it comes to memory foam, density and firmness matter. 

Manufacturers weigh a 12x12x12-inch piece of foam to determine its density, measured in pounds per cubic foot. 

If it weighs 3 pounds or less per cubic foot, it’s considered low-density foam. It’s super soft and gives you that cozy, cradling feeling. On the other hand, if it weighs 6 pounds or more, it’s higher-density memory foam. This one’s firmer, more durable, and can handle serious pressure, especially for heavy-weight sleepers

Now, let’s talk about firmness. It’s measured using indentation load deflection, ILD for short. 

The higher the ILD, the firmer the foam feels. But don’t get too caught up in the numbers! ILD is just a rough guide. You have to consider how the mattress feels overall and what you prefer. 


You might notice an off-gassing smell when you first get a memory foam mattress or with memory foam mattress pads and pillows. 

It’s normal and happens because of volatile organic compounds (VOCs). When the memory foam is unpacked, these compounds can give off an unpleasant odor. 

Don’t worry, though! The smell is temporary and usually lasts for just a few days. It’s more noticeable with lower-quality foam that has more of these compounds. 

So, while you may not be able to avoid it altogether, know that it’s a normal part of the process and will fade away soon. However, VOCs can harm children, so air the mattress well if a child is supposed to sleep on it. 

Temperature Regulation

Unfortunately, traditional memory foam tends to trap heat. But fortunately, newer technologies like gel memory foam help with this, and hot sleepers love it. 

As mentioned before, the gel pods in memory foam absorb and release heat from your body, creating a cooling experience. This mattress material is usually a bit firmer and more bouncy, but it’ll still contour to your body and relieve pressure. 

Hot sleepers can also go for open-cell memory foam. This material is made more breathable with the help of little air pockets throughout it. Copper-infused foam is also a good option for hot sleepers. 

Sleeping Position

The perfect mattress for you also depends on the position you sleep in. Different sleeping positions mean that your spine and your body have to be supported in different ways. 

Here’s how a memory foam mattress works with typical sleeping positions: 

  • Side sleepers: memory foam is an excellent choice because it keeps the spine aligned while letting the hips and shoulders sink into the mattress. It also gives them enough pressure relief, which is always a plus. Side sleepers should sleep on a softer memory foam. 
  • Back sleepers: Keeping their spine aligned is easy for back sleepers, so they need a supportive mattress that won’t let their lower back sink in too much. A medium-firm to firm memory foam mattress can do the trick for back sleepers
  • Stomach sleepers: even though they’re in a tricky position for their backs, stomach sleepers need a firmer mattress that won’t let their hips sink in too much. 
  • Combination sleepers: they change positions often, so combination sleepers should look for a bed with a fast response. Memory foam can offer support and comfort in other positions, but the slow response of a memory foam bed might not be everyone’s cup of tea. 

Body Weight

The more pressure you put on the mattress, the firmer it should be. Many memory foam products come with a weight capacity, indicating the maximum body weight they can support while maintaining quality. Firmness plays a crucial role here too. 

Here’s what you need to know: 

  • Light-weight sleepers under 130 pounds: since they don’t put much pressure on the mattress, they should go for a softer mattress. 
  • Average-weight sleepers between 130 and 230 pounds: a medium-firm mattress should fit average-weight sleepers the best, but it also depends on their sleeping position. 
  • Heavy-weight sleepers over 230 pounds need a firmer mattress that’s also more supportive, so they should go for a high-quality or hybrid memory foam mattress. 


When shopping for a memory foam mattress, it’s essential to consider the quality and safety of the foam used. 

Lower-quality mattresses may contain additives that can degrade the material, shorten its lifespan, and potentially harm you. To ensure you make an intelligent choice, look for a CertiPUR-US certification.

The CertiPUR-US seal of approval guarantees that the memory foam in the mattress is free from harmful chemicals. You can rest easy knowing that these certified mattresses are made without mercury, lead, heavy metals, formaldehyde, phthalates, and PBDEs.

They also have lower levels of volatile organic compounds (VOCs) responsible for off-gassing. 

So make sure to take some time to check whether that mattress you had your eye on has a CertiPUR-US certification. It’s vital for your health and comfort. 


How much does a memory foam mattress cost? Memory foam mattresses fall into a pretty wide price range. 

You can get a memory foam mattress for a very affordable price if you’re looking for a budget mattress. However, very cheap memory foam beds are usually made from very cheap and low-quality materials. This can make them less comfortable and less durable. 

If you want a high-quality memory foam mattress with good density, ILD, and special features such as cooling, you’ll need to shell out some extra cash. Remember to look for high-density foams if you want high-quality!

You can also find pretty good quality foam mattresses in a lower price range; you just have to do your research. 

Memory Foam – Pros and Cons

As with anything, memory foam also comes with pros and cons. We already mentioned some of them, but let’s take a more detailed look. 


  • Contouring: memory foam contours to the shape of the body extremely well.
  • Supportive: a mattress is supposed to take care of your spinal alignment and offer lumbar support when lying down, and memory foam does an excellent job. 
  • Suitable for all sleeping positions: memory foam mattresses are a good choice no matter which position you sleep in because they can offer support and comfort, depending on their firmness. 
  • Pressure relief: if you suffer from back pain or joint pain, memory foam is there to save the day! This material offers impressive pressure point relief for any pressure points, and it’s usually better at this than other mattresses.  
  • Motion isolation: because it absorbs pressure and impacts to the sleep surface so well, evenly distributing weight, you won’t feel your sleeping partner tossing and turning while sleeping on a memory foam mattress 
  • Hypoallergenic: because they’re so dense, memory foam mattresses can’t hold that many common allergens, like dust mites.
  • No noise: memory foam handles noise like it handles impact, so you won’t have to worry about getting a noisy mattress over time. 
  • Adjustable beds: their construction makes it possible to use memory foam for adjustable beds.


  • Body heat retention: traditional memory foam mattresses are notorious for trapping body heat, but you can use gel-memory or open-cell memory foam if you sleep hotter.
  • Feeling like you’re stuck: memory foam mattresses contour your body well, but the feeling of being stuck might not be everyone’s cup of tea
  • Off-gassing: memory foam mattresses off-gass when you open them, but it’s gone in a few days. 
  • Not waterproof: whatever you do, don’t get your memory foam mattress wet, as it can develop mold and bacteria. 
  • Expensive: high-quality memory foam mattresses cost a lot. 

Who Should Buy a Memory Foam Mattress?

A memory foam mattress is an excellent option for a variety of people. If you want a mattress that relieves pressure, molds to your body, and feels super comfy, then memory foam is the way to go! It’s the best mattress type for side sleepers. 

It’s perfect for those who love that soft, cozy feel and want to minimize pain or motion transfer. That’s why couples love it!

If you’re looking for comfortable and supportive sleep, a memory foam mattress is a fantastic choice!

Frequently Asked Questions

How Long Does Memory Foam Last?

Your memory foam mattress can provide lasting comfort for seven to ten years with proper maintenance. Taking care of it is essential for its durability. Keep it dry and away from heat sources to maximize its lifespan. Also, rotate it occasionally, especially if the mattress care instructions say so. 

How Do I Clean My Memory Foam Mattress?

You should clean and deodorize your mattress every couple of months. It’s pretty straightforward – it’s all about vacuuming, removing stains, and not wetting it too much. 

Need more information? Check out our article on how to clean a memory foam mattress

Are Memory Foam Mattresses Good for Back Pain?

Yes, memory foam is an ideal choice for people who suffer from back pain. It gives support, contours, and relieves pressure enough to manage joint pain while keeping the spine aligned. 

Final Thoughts

Memory foam is a soft, contouring material that relieves pressure and provides motion isolation. It can also get pretty hot, but you can go for open-cell foam or gel foam to deal with that problem. 

What do you think? Is memory foam the perfect choice for you? 

We wish you a good night’s sleep! 

Reviews written by:

Andjela Kastratovic - Co-editor

Anđela is a content writer by the day and an Illustrator by night. She loves anything creative, but sleep takes the cake – that’s why she enjoys writing for Anatomy of Sleep so much!

While in high school, she got accepted for her dream job – a ‘professional sleeper’. Her job was to test new mattresses from a local mattress brand and write reports on the quality of sleep. Ever since then, she’s been in love with reviewing mattresses and putting her compelling research into ultimate buyer’s guides. While not exploring the latest brands, she likes to illustrate and spend time with her dog and friends.