What Is Memory Foam?
Everything You Need to Know


Written by David Rubin

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Many modern mattresses include memory foam in their construction. Though it was originally created for a different purpose, today, you can find the unique material in mattresses, pillows, and other bedding.

NASA developed memory foam, a type of polyurethane foam, in the 1960s. They incorporated the foam into the seats and seatbelts of space shuttles because the material absorbs shock and relieves pressure exceptionally well. Additionally, memory foam contains additives that make it viscoelastic, meaning it has more viscosity and elasticity than standard polyfoam.

If you use your hand to apply pressure to memory foam, the foam cushions and contours around it, following your hand’s shape. When you remove your hand, it leaves an imprint that slowly disappears as the foam retains its original shape.

Tempur-Pedic was the first company to use memory foam in mattress construction starting in the 1990s. Many other manufacturers have since adopted the material, making memory foam widely used in sleep products.

We’ll explore the different types of memory foam, take a look at how it works, and discuss the pros and cons of owning a memory foam mattress.

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What Types of Memory Foam Are There?

As is the case with any kind of mattress, memory foam mattresses are not one-size-fits-all. It’s important to consider your body weight and sleep habits, as well as personal preferences, when determining which mattress you should buy.

Over time, mattress manufacturers have made adjustments to memory foam to enhance its performance. Many companies have their own patented formulations, though most memory foam falls under one of the following three categories.

Standard Memory Foam: This is the original or traditional type of memory foam. It’s designed to contour closely to your body and evenly disperse your weight, providing deep relief for pressure points and joint pain. Standard memory foam often retains body heat and can feel uncomfortably warm because air doesn’t circulate well within the foam’s internal structure.

Open-cell Memory Foam: Open-cell memory foam was formulated to combat the heat retention commonly found in traditional memory foam mattresses. The open-cell design leaves additional room for airflow and ventilation, helping the mattress sleep cooler.

Gel Memory Foam: Gel memory foam is also designed to help your mattress stay cool. Gel microbeads are infused directly into the memory foam to create additional open space for air circulation. The gel typically consists of a phase change material (PCM) that helps regulate body temperature by absorbing excess heat.

Foam beds are often considered best for side sleepers as they contour to your body, providing support and helping with those occasional aches and pains. They’re also really good if you’re a light sleeper or sleep with a partner and you don’t want movement to wake you up at night.
Dr. Michael Breus

Does Memory Foam Off-Gas?

Memory foam often has a chemical-like smell when first removed from the packaging. This is due to the release, or off-gassing, of volatile organic compounds (VOCs), which are created during synthetic foam manufacturing. The VOCs emitted from synthetic foams are not associated with any health risks, but off-gassing odors can be problematic for those who have respiratory issues or a sensitivity to smell.

You can avoid unpleasant odors by unrolling your mattress in a well-ventilated area and waiting at least 24 hours before use. VOCs typically dissipate within this timeframe, though some mattresses that use less expensive materials may require more time for the odors to fully vaporize.

How Does Memory Foam Compare to Polyfoam?

Though memory foam and polyfoam share some common characteristics, their performance and use can vary widely. Both types of foam compress easily, making them excellent choices if you’re looking to purchase a mattress in a box. However, the foams have different densities, with high-density memory foam typically having a greater pound per cubic foot (PCF) rating than high-density polyfoam.

Though performance and quality can vary by manufacturer, memory foam has a consistent feel, and nearly all iterations of memory foam share similar characteristics. On the other hand, polyfoam can be formulated in many different ways, which gives it greater versatility than memory foam. Generally, only mattress comfort systems include memory foam, while all mattress layers can include polyfoam.

Memory Foam vs. Polyfoam

Foam Type

Memory Foam

Memory foam provides top-notch pressure relief and body contouring. It disperses weight evenly, is virtually silent, and is unlikely to transfer movement from one end of the bed to the other.

  • Beneficial for people with joint pain and those who feel pressure points while sleeping
  • Excellent motion isolation
  • Dense foam has a longer lifespan
  • Sleeps warmer than other foam
  • Can be expensive
  • Some people may not like the feeling of sleeping in rather than on their mattress


Polyfoam is highly versatile. Mattress manufacturers can layer different formulations of polyfoam to create distinct feels and performances. It generally sleeps cooler than memory foam and often costs less.

  • Typically has better airflow than memory foam
  • Available in many different firmness levels
  • Can be formulated to mimic latex
  • Cheaper polyfoam beds may have a shorter lifespan
  • Has a lower average density than memory foam
  • Doesn’t contour as closely as memory foam

How Does Memory Foam Perform in a Mattress?

Memory foam appeals to users for its ability to contour closely, absorb pressure, and reduce motion transfer. However, there are additional factors to consider when shopping for a mattress that includes memory foam.

Pressure Relief: Memory foam excels at relieving pressure. The material evenly disperses body weight across the mattress’ surface, reducing force under pressure-prone body parts such as the hips and shoulders. Additionally, memory foam hugs these areas, providing substantial cushioning that alleviates pressure buildup.

Contouring: While you sleep on a memory foam mattress, the foam contours closely to your body’s shape, mimicking a hugging sensation. When you get up, your body leaves an imprint, or memory, in the foam. This contouring effect helps minimize pressure and prevent movement from transferring across the bed.

Motion Isolation: Memory foam has little to no bounce, which gives it an advantage when it comes to motion isolation. Instead of allowing movement to transfer across a bed’s surface, memory foam absorbs and traps it where it occurs. This can be particularly helpful for couples, who are unlikely to be disturbed by their partner’s movement.

Edge Support: Some memory foam mattresses lack the perimeter reinforcement that innerspring or hybrid beds have. Because the foam is designed to compress, you may find that your memory foam mattress sinks if you sit on the mattress’ edge. Shoppers who have a hard time getting in and out of bed may want to consider a model that has enhanced edge support.

Temperature Control: Memory foam is designed to absorb body heat, which can make it uncomfortable for people who sleep hot. Because of its density, air doesn’t circulate easily, and heat can become trapped within the foam. While open-cell and gel-infused foams target this issue, most memory foam mattresses will still retain more heat than their innerspring or hybrid counterparts.

Why Is Density Important in a Memory Foam Mattress?

Density measures how much foam is present in a mattress layer. Mattress manufacturers measure density in pounds per cubic foot (PCF), meaning how many pounds are present in a given piece of foam. The higher the number, the denser the foam. Most memory foams fall between 3.5 and 5 PCF, though some foams fall outside that range.

High-density foam generally has a longer lifespan than low-density foam. Because high-density options have more foam present per cubic foot, it takes longer for the material to break down. However, high-density foam traps heat easily, so shoppers have to weigh the pros and cons of foam densities before purchasing. Many mattress companies effectively layer different density foams to achieve the best performance possible.

Memory Foam Densities

Foam Type


The internal structure has more room for air to circulate, so it achieves better temperature neutrality.

Low-density foam will break down and sag faster than high-density foam.


Medium-density foam is a good fit for shoppers who want to bridge the gap between durability and heat retention.

While it’s more durable than low-density foam, this style won’t have the lengthy lifespan of high-density foam.


High-density foam is very durable and will help increase a mattress’ longevity.

Hot sleepers may find high-density foam retains too much body heat to allow for a comfortable sleep.

Are Memory Foam Beds Expensive?

Memory foam mattresses often cost more than basic polyfoam models because of the high-quality materials used to manufacture them. Memory foam has a higher density than other types of foam, contributing to a higher price tag. Factors like thickness, certifications, and added cooling technologies can also affect the cost of memory foam beds.

How Long Do Memory Foam Mattresses Last?

Most mattresses last about 6 to 8 years, and the average memory foam mattress is no exception. However, high-quality memory foam mattresses that are properly cared for can last up to 10 years, while beds consisting of cheaper materials may only have a lifespan of 3 to 5 years.

Mattress density can directly affect how long your bed will last. High-density foams resist pressure and force well, which means they won’t sag or break down as quickly as their low-density counterparts. Properly caring for your mattress by using a mattress cover can also help lengthen its lifespan, as it protects the bed from normal wear and tear. Consider a mattress’ warranty length and coverage before making a purchase.

About The Author

David Rubin

Certified Sleep Science Coach, Director of Product Testing

David is a Certified Sleep Science Coach with a lifelong passion for well-being and health optimization. His interest in sleep developed with the arrival of his son, when sleep suddenly became a precious commodity.

  • POSITION: Side Sleeper
  • TEMPERATURE: Hot Sleeper

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