Mattress

A pillow top queen-size mattress.

A mattress is a mat or pad, usually placed on top of a bed, upon which to sleep or lie.

The word mattress is derived from Arabic words meaning "to throw" and "place where something is thrown" or "mat, cushion." During the Crusades, Europeans adopted the Arabic method of sleeping on cushions thrown on the floor, and the word materas eventually descended into Middle English through the Romance languages.^[1]

Though a mattress may be placed directly on the floor, it is usually placed on top of a platform (such as a platform bed or a metal box-spring or a slatted foundation) to be further from the ground. Historically, mattresses have been filled with a variety of natural materials, including straw and feathers. Modern mattresses usually contain either an inner spring core or materials such as latex, viscoelastic, or other polyurethane-type foams. Mattresses may also be filled with air or water, or a variety of natural fibres, such as in futons.

History

Photo on a 1940 USDA circular promoting home production of cotton mattresses

• Neolithic period: The mattress and bed are invented. Beds are raised off the ground to avoid drafts, dirt, and pests. The first mattress probably consists of a pile of leaves, grass, or possibly straw, with animal skins over it.
• 3600 B.C.: Beds made of goatskins filled with water are used in Persia.
• 3400 B.C.: Egyptians sleep on palm boughs heaped in the corners of their homes.
• 200 B.C.: Mattresses in Ancient Rome consist of bags of cloth stuffed with reeds, hay, or wool; the wealthy use feather stuffing.
• 15th century: During the Renaissance, mattresses are made of pea shucks, straw, or sometimes feathers, stuffed into coarse ticks, and covered with velvets, brocades, or silks.
• 16th and 17th centuries: Mattresses are stuffed with straw or down and placed atop a bed consisting of a timber frame with support latticeworks of rope or leather.
• Early 18th century: Mattresses are stuffed with cotton or wool.
• Mid 18th century: Mattress covers begin to be made of quality linen or cotton. The mattress cane box is shaped or bordered, and fillings include natural fibers such as coconut fibre, cotton, wool, and horsehair. The mattress is tufted or buttoned to attach the stuffing to the cover and the edges are stitched.
• Late 19th century: The box-spring is invented, making mattresses less lumpy.
• 1930s: Innerspring mattresses and upholstered foundations become widely used, and artificial fillers become common. Encased coil spring mattresses, which consist of individual springs sewn into linked fabric bags, are introduced.
• 1950s: Foam rubber mattresses and pillows are available for purchase.
• 1960s: The modern waterbed is introduced and gains its first widespread use. Adjustable beds gain popularity.
• 1970s: NASA invents material that later becomes known as memory foam^[2].
• 1980s: Air mattresses constructed of vulcanized rubber or vinyl are introduced.
• 1992: Tempur-Pedic introduces a mattress made from memory foam.
• 1992: Fibrelux introduces a mattress made from rubberized coir.

Mattress dimensions

Mattresses thicknesses range from four to eighteen inches (10 to 46 cm).

A comparative diagram of some U.S. mattresses

A comparative diagram of some UK mattresses

Components of an innerspring mattress

Pocket springs

A common innerspring mattress consists of three components: the spring core, the foundation, and the upholstery layers.^[4]

Spring mattress core

The core of the mattress supports the sleeper’s body. Modern spring mattress cores, often called "innersprings," are made up of steel coil springs, or "coils."

The gauge of the coils is another factor which determines firmness and support. Coils are measured in quarter increments. The lower the number, the thicker the spring. In general, higher-quality mattress coils have a 14-gauge (1.63 mm) diameter. Coils of 14 to 15.5-gauge (1.63 to 1.37 mm) give more easily under pressure, while a 12.5-gauge (1.94 mm) coil, the thickest typically available, feels quite firm.

Connections between the coils help the mattress retain its shape. Most coils are connected by interconnecting wires; encased coils are not connected, but the fabric encasement helps preserve the mattress shape.

Here are five types of mattress coils:

• Bonnell coils are the oldest and most common. First adapted from buggy seat springs of the 19th century, they are still prevalent in less expensive mattresses. Bonnell coils are hourglass-shaped, and the ends of the wire are knotted or wrapped around the top and bottom circular portion of the coil and self-tied.
• Marshall coils are each wrapped in a fabric encasement and usually are tempered. In the case of Beautyrest, high carbon magnesium is added, while the steel itself remains untempered. Some manufacturers pre-compress these coils, which makes the mattress firmer and allows for motion separation between the sides of the bed.
  

  Bonell springs
• Encased Coils or encased springs, are a component part of a mattress in which each coil is separately wrapped in a textile material. Encased coils may also be generically referred to as Marshall coils or wrapped coils.
• Offset coils are designed to hinge, thus conforming to body shape. They are very sturdy, stable innersprings that provide great support.
• Continuous coils Or Mira-coils, work by a hinging effect, similar to that of offset coils. In a basic sense a continuous coil is simply that, one continuous coil in an up and down fashion forming one row (usually from head to toe) of what appear to be individual coils. The advantages of how firm a support the continuous coil provides it is somewhat tempered with the "noise" associated from a typical Mira-coil unit. The largest company using a Mira-coil design, is Serta Mattress Company, though their coil units are supplied by Leggett & Platt.

Bonell springs are hour-glass shaped, which means their resistance increases with load. They are therefore best suited for firm mattresses.

Pocket springs provide support along the entire length of the body. This design works to maintain natural spinal alignment throughout the night.

Air mattresses

Air mattresses use one or more air chambers instead of springs to provide support. Quality and price can range from inexpensive ones used occasionally for camping, all the way up to high-end luxury beds. Air mattresses designed for typical bedroom use cost about the same as inner-spring mattresses with comparable features.

Air mattresses as regular beds

Several companies currently produce adjustable firmness air mattresses. In 1981, Comfortaire began manufacturing and marketing air mattresses that looked conventional, but allowed users to adjust the firmness. Select Comfort patented a variant and began marketing them in 1987. Today, Select Comfort produces the Sleep Number bed which allows couples to independently adjust each side of the bed to their individual preference for comfort and firmness^[5].

Adjustable air mattresses come in a variety of models from basic, no-frills ones that measure about 7" in height, to high-profile, 15" tall hybrids that contain several types of foam, pillow tops, and digital pumps with memory, for individual pressure settings.

Air bladder construction varies from a simple polyethylene bag to internally baffled, multiple chambers of latex (vulcanized rubber) with bonded cotton exteriors. Mattresses have a layer of foam above the air chambers for added cushioning. The air chambers, top and sidewall foam all sit inside a removable two piece cover that looks like the outside of a standard innerspring mattress. These high-end luxury Air Beds are also known as soft sided Air Beds.

Air mattresses for medical use

Medical versions of adjustable firmness mattresses have special control mechanisms. In 1990s, the industry began producing self-adjusting air beds that automatically change their pressure periodically, and/or inflate and deflate several air chambers alternately. The intention of these periodic changes is to reduce problems with decubitus ulcers (bed sores), though it is still a subject of research how effective this is.^[6]

Self-inflating air mattresses

Air mattresses for camping are often filled with foam. The foam itself provides little support, but will expand when the mattress' air valve is opened, and draw in air, so the mattress will (nearly) inflate by itself. This is especially useful for hikers, as unlike normal air mattresses no pump is needed for inflating. A common brand is Therm-a-Rest.

Foam mattresses

Foam mattresses use shape-conforming latex or viscoelastic memory foam plus polyurethane flexi-foam to provide better support than springs alone, as well as in combinations of springs and foams. Latex mattresses generally come in two types of Latex, Talalay and Dunlop, which are manufactured differently and provide different feels as well as different qualities. Mattresses manufactured using memory foam or latex are generally hypoallergenic. Since foam varies in quality, prices can vary widely. Most mattress manufacturers offer a line of memory foam mattresses.

Foundation

There are three main types of foundations.

• Box-springs consist of a rigid frame that contains extra-heavy-duty springs. This type of foundation contributes to softer support and a bouncier mattress. Because box-springs can cause mattresses to sag, many manufacturers add high-density block foam underneath the coils or provide a rigid foundation instead.
• Traditional wood foundations are usually made of soft woods, such as pine, or hard woods. They usually consist of seven or eight support slats covered with paperboard or beaverboard. This type of foundation, called a zero deflection unit or an "Ortho Box" in the bed industry, increases the feeling of firmness and stability.
• Grid foundations are a combination of steel and wood.

Upholstery layers

Upholstery layers cover the mattress and provide cushioning and comfort. Some manufacturers call the mattress core the "support layer" and the upholstery layer the "comfort layer." The upholstery layer consists of three parts: the insulator, the middle upholstery, and the quilt.

The insulator separates the mattress core from the middle upholstery. It is usually made of fiber or mesh and is intended to keep the middle upholstery in place.

The middle upholstery comprises all the material between the insulator and the quilt. It is usually made from materials which are intended to provide comfort to the sleeper, including regular foam, viscoelastic foam, felt, polyester fibers, cotton fibers, convoluted ("egg-crate") foam, and non-woven fiber pads.

The quilt is the top layer of the mattress. Made of light foam or fibers stitched to the underside of the ticking, it provides a soft surface texture to the mattress and can be found in varying degrees of firmness. The protective fabric cover which encases the mattress is called ticking. It is usually made to match the foundation and comes in a wide variety of colors and styles. Most ticking is made of synthetic fibers like polyester, or acrylic; or of natural materials such as latex, cotton, silk, and wool.

Quality

Many parameters determine mattress quality. Laboratory test methods have been established for some of these parameters, such as pressure distribution, skin microclimate, hygiene, edge support, and long-term stability. Many of these have been developed by Dr. Duncan Bain, working on behalf of the UK's Medicines and Healthcare products Regulatory Agency.^[7]

Other parameters, such as firmness, are more specific to the sleeper. In general, firm mattresses are recommended for stomach and some back sleepers, soft mattresses are recommended for side sleepers, and medium mattresses are recommended for the majority of back sleepers. Some brands offer mattresses with one softer side and one firmer side, or with adjustable firmness levels, to accommodate sleepers who share a bed.

Maintenance and care

A quality innerspring mattress should last between 7 and 10 years before it needs to be replaced. Memory foam and latex models should last between 10 and 20 years, depending on the manufacturer, the quality of the bedding, and the vigorousness of use. This is an approximation, as many factors affect the lifespan of a mattress.

Mattresses should be placed atop a firm base to prevent sagging. A new mattress should be rotated once a month for the first six months and once every 2–3 months after that. Double sided, or two sided, mattress should be alternately flipped and rotated. Manufacturers suggest that one rotate (spin) the box springs or foundation twice a year. Folding and bending of the mattress should be avoided if possible, as should heavy wear in one spot and excessive weight on the handles. Mattresses should not be soaked, lest mildew develop inside the upholstery; instead, they can be cleaned with a vacuum or with mild surface cleanser and a slightly damp cloth. Mattress Protectors help prevent stains and soiling of the ticking.

Once a mattress no longer feels supportive and instead seems to contribute to body pain or stiffness, it should be replaced. Some symptoms of a broken or worn out mattress include springs which can be felt poking through the upholstery layer, visible permanent sagging or deformity, lumpiness, and excessive squeaking.

Queen and larger size mattress sets should be supported by a 5- or 6-leg frame. A queen size mattress is 60 inches wide and requires more support than smaller sizes. If using a headboard/footboard style bed, one should use at least five wood slats with three positioned primarily in the center third of the bed.

See also

Notes