Sleepology Resource Center
What types of foams are used for mattresses?
Are innerspring mattresses better than foam mattresses?
What are pocketed springs, and what are they useful for?
What’s the difference between a regular mattress and a cooling mattress?
What type of foundation should I have for my bed?
What type of pillow should I get?
Does the firmness of my pillow matter?
What type of sheets are best for me?
What type of mattress is best for back sleepers?
What type of mattress is best for side sleepers?
What type of mattress is best for stomach sleepers?
What type of mattress is best for back pain?
What type of mattress is best for sleep apnea?
Mattress Basics
Mattress Construction
and Layers
Comfort Layers
Comfort layers are usually the uppermost layers that are designed to be softer and gentler on your body. Comfort layers compress to help relieve pressure points by contouring the curves of your body, especially around the hips, shoulders and knees.
Depending on the firmness level of the mattress you choose, comfort layers can be anywhere from 1” to 8” thick. Most of the time, the softness of your bed is determined by the thickness and material of these upper comfort layers. The most common materials used for top comfort layers are:
Latex Foam
Latex is a form of foam made either from the material extracted from rubber trees, or from synthetic methods that produce foam that feels just like latex. Latex can be all-natural (NR), synthetic (SBR) or—most commonly—a synthetic/natural blend.
The hallmark of latex foam is its responsiveness, which reacts quickly to movement while continuing to hug the body. Some consider latex or latex alternative foams to have more “bounce” with motion isolation superior to that of traditional polyurethane foams. Latex is a popular material for mattress comfort layers because it is naturally breathable and soft.
Polyurethane FoamPolyurethane foam is a type of synthetic foam material that comes in many different firmness levels. It compresses easily like many latex foams but, because of its lower density, tends to break down more quickly.
Polyurethane foam is the most affordable of foam options and is often used as both a comfort or a transitional layer in hybrid mattresses featuring springs.
Memory FoamMemory foam is a popular type of foam, frequently used in comfort layers due to the slow response attributes of visco-elastic. Its moldability delivers superior pressure point relief and motion isolation. Rather than quickly returning to its form after pressure is released, memory foam reacts to heat in order to compress. This is why memory foam feels as if it “hugs” the body.
Memory foam is great for sleepers who have a hard time getting comfortable in bed but, given its slow response to movement, it can sometimes produce a “quicksand” feeling, like being “stuck” in the bed. Memory foam is often used in combination with other types of foam for upper comfort layers.
Should I get a memory foam mattress or a latex foam mattress?
Memory foam and latex foam both offer contouring and pressure point relief but do so in different ways. The main difference is how quickly each type “responds” to movement. Memory foam is a slow response foam, which means you sink more as your body temperature warms and it molds to the unique contours of your body.
Latex or latex alternative foam is a quick response foam, which feels bouncier and responds to movement more quickly. Some prefer this feeling since it is easier to adjust and move throughout sleep , while others like the cozier feel of memory foam.
Comfort layers are an important buffer between the body and firmer support layers. Many beds include various infusions in comfort layer foams to aid in breathability, body temperature regulation and cooling.
More about cooling in mattresses here.Transitional Layers
Not all mattresses have transitional layers. Those that do compensate for the wide difference in density between top comfort layers and support layers.
Transitional layers are designed to create a gentler and less noticeable transition between soft top layers and firm core layers. Depending on how the mattress is constructed, the transitional layer may be convoluted, or cut to have an uneven surface that looks like small “hills and valleys”. Convoluted transitional layers aid in breathability by providing open pockets where heat can more easily be dispersed.
Support Layers
Support layers are denser layers at the core or bottom of a mattress. Support layers do the hard work when it comes to providing spinal alignment, lumbar support and overall durability and structural integrity. Support layers are made of a variety of materials, including:
Foam
Many all-foam beds create a support layer using a foam with a higher ILD, or a firmer feeling foam. These firmer foams tend to last longer and provide minimal compression while helping reduce excessive sinking that can jeopardize spinal alignment and back health.
Because they absorb movement better than traditional box springs, they can also aid in reducing motion transfer from one side of the bed to the other.
Traditional Innersprings or “Open Coils”Traditional innersprings are similar to pocketed springs, but are either woven or linked together with metal or string. Open coil innersprings tend to be cheaper and easier to produce than pocketed springs, but don’t provide independent compression of coils.
While traditional innersprings are both supportive and durable, they can sometimes feel “bouncy”. Sleep partners can also more easily feel movement from one area of the bed to another.
Individually Pocketed SpringsIndividually pocketed springs are constructed by encasing each coil with a non-woven fabric. This individualized style of support combines targeted relief with motion isolation since each spring can compress independently. Weight is distributed across deeper compressed areas while the base maintains its overall form.
The firmness of pocketed springs is determined by the gauge of the metal—the thicker the gauge, the more firm the feel. Tempering (a process of heating and cooling) ensures coils maintain their intended shape after numerous compressions. Both innersprings and pocketed springs offer more open areas for heat to disperse, making them cooler overall than all-foam mattresses.
Mattress Basics
Types of Mattresses
Despite popular belief, there is no one mattress type that is inherently better than others. Every type of mattress delivers on the needs and wants of particular types of sleepers. That said, there are general differences between each type of mattress-knowing a bit about each can help you narrow your search for the perfect bed.
All-Foam Mattresses
All-foam mattresses have been around for decades, but a recent upswing in online-only mattress retailers means that all-foam mattress construction has gained popularity. All-foam mattresses are usually more affordable and easier to care for—but they have less adaptability and ability to cater to more complex sleep needs.
All-foam mattresses are usually made of a combination of latex, memory or polyurethane foam. The thickness, ratio and number of different foam layers in all-foam mattresses will determine the feel, durability and comfort characteristics of the bed.
The idea that layers do not have a significant impact on comfort or quality is a myth. Foam layers are designed to work together to deliver comfort and support, not independently. It is rare for high quality manufacturers to produce mattresses that are made of only one or even two layers of foam.
Innerspring Mattresses
Innerspring mattresses are primarily constructed with an interconnected series of springs or coils covered by a layer of wool, foam and filling. Traditional innerspring mattresses were the most common type of mattress for decades and, while they were affordable and easy to find, they were interwoven with metal and weren’t especially comfortable.
Hybrid Mattresses
Hybrid mattresses give sleepers the perfect blend of sturdy support and contouring comfort. They combine an innerspring system—typically individually encased coils—with foam layers to deliver the best of both technologies. Depending on the mattress, there can be anywhere from one to multiple layers of latex, memory or polyurethane foam to deliver additional benefits.
What’s better for me—a hybrid mattress or an all-foam mattress?
Choosing between a hybrid or all-foam mattress is really a matter of preference as long as your mattress is made with the highest quality materials. The major distinctions between each mattress come down to overall feel, breathability and motion isolation.
Foam mattresses provide moldable and deeper contouring with the feeling of sleeping "in" the mattress. Hybrid mattresses provide a more traditional feel of sleeping “on” the mattress. Both can deliver exceptional pressure point relief and support but will feel differently to each sleeper.
Many sleepers love the feel of all-foam mattresses but find they sleep too hot. Because hybrid beds feature coils in the core, rather than a dense foam layer, hybrids will inherently be cooler. That said, many foam beds now offer advanced cooling technology in surface layers that help regulate temperature.
Hybrid mattresses, featuring individually pocketed springs, are the clear choice if you’re concerned about motion transfer between your sleep partner and you. Encased coils are designed to compress independently of one another, decreasing sleep disturbance when one of you moves in bed. If you do choose an all-foam bed, both latex and latex alternative foams offer better motion isolation than polyurethane foam layers.
Mattress Basics
Breathability vs. Cooling
Breathability
Most mattresses deliver some form of breathability or cooling, but the way in which that cooling is delivered will affect how cool you sleep overall.
Breathability refers to how easily air can circulate through the mattress and, thus, how easily body heat can be dispersed. Most mattresses are designed to offer at least some breathability since sleeping too hot or experiencing night sweats is a major contributor to insomnia. Breathability in mattress construction is achieved through the following:
Open Cell Foam
Open cell foam refers to a type of foam designed to allow for freer airflow through the material. Open cell technology is critical to body heat regulation while sleeping since heat can otherwise become trapped, causing your body temperature to increase. Open cell foam, while promoting better breathability, does not offer active cooling.
Convoluted Transitional LayersConvoluted transitional layers can have an effect on a bed's overall breathability since convoluted foam creates small pockets through which heat can more easily disperse.
Cooling
Cooling is achieved by adding different infusions either to the cover or top comfort layers of a bed. Not all beds are designed with cooling technology, a premium feature usually reserved for higher-end beds. Advanced cooling is usually achieved with a combination of different cooling elements and infusions, including:
Gel Infusions
Gel infusions, sometimes referred to as a gel "swirl", are added during the production of the foam. Gels pull heat out and away from a bed's top layers and into the core of the mattress, keeping the surface and top layers cooler. Cooling gel is a popular infusion for memory foam given its tendency to conform based on body heat.
Metallic InfusionsAnother form of a cooling infusion is a metallic infusion, including copper graphite and titanium. These metallic additives conduct heat more effectively, which means they are more capable of pulling heat out and away from the body, moving it further down into the core of a mattress. Unlike gel infusions, however, they do not generally feel cool to the touch.
Phase Change Surface Infusions
The most advanced cooling mattresses will double down on cooling with a phase change molecule (PCM) surface infusion that provides cooling on contact. Unlike infusions in top foam layers, surface infusions are added to the top cover of your mattress that often make your bed feel cool even with a fitted sheet.
PCM suface infusions work by moderating your body temperature using cooling gel beads. If your skin is above 88 degrees (the optimal sleep temperature), the gel beads change to a liquid state to actively cool your body temperature. Once your body is at or under 88 degrees, the gel beads change to a solid state to simply maintain the ideal body temperature.
Should I invest in a mattress that has cooling technology?
Breathability is important for all sleepers but not everyone will need or want a bed with advanced cooling technology. If you don’t tend to wake up clammy or sweaty, or don’t notice waking up feeling overly warm, a cooling mattress might not be necessary. If you tend to wake up feeling sweaty or constantly kick off the covers to stay cool, a mattress with advanced cooling technology is likely a good choice.
Mattress Basics
Mattress Sizes and Dimensions
Depending on your sleep needs, budget and size constraints, selecting the correct mattress size is an important decision. Below are general guidelines.
Twin and Twin XL Size Mattresses (39 x 74, 39 x 80)Twin and Twin XL mattresses are both designed for children or tweens, though you can sometimes find Twin XL mattresses in college dorm rooms. Twin mattresses are great for kids since they offer the right amount of sleep space but can still be used in smaller bedrooms and with furniture like bunk beds. They are generally not a suitable choice for most teenagers or adults on a long-term basis.
Some adjustable bases are designed to accommodate two Twin XL mattresses rather than a single king size mattress, which allow for independent sleep positions for each person.
Full Size Mattresses (54 x 74, 54 x 80)The full size mattress, also known as a double mattress, is approximately 16 inches wider than a twin mattress. It is not recommended for paired sleepers and may be too short for adults who are taller than 5'5”. Full beds, however, are widely used by single sleepers desiring additional width and are especially practical for an individual with a smaller bedroom.
Queen Size Mattresses (60 x 80)Queen mattresses are the most popular size, since they can comfortably fit one or two sleepers most of the time, and fit well in large or small rooms. Queen mattresses are great for paired sleepers who don’t need much extra room and don’t anticipate children or pets sharing a sleeping surface with them.
King and California King Size Mattresses (76 x 80, 72 x 84)King and California King are usually reserved for those who prefer a bit of extra room and have the space to accommodate them in their bedrooms. California King, on average, is about four inches longer and four inches narrower than King size mattresses, so they can be a great option for sleepers who are very tall.
Custom Mattress SizesSome companies can create custom sizes for sleepers that require specific dimensions for their beds. These sizes are often grouped into an Olympic Queen (66 x 80), a California Queen (60 x 84), and a Short Twin (34 x 75). Some companies can also create mattresses in completely unique dimensions, but this may add significantly to the cost of the mattress.
