This rusty box spring sits on a curb waiting to be picked up. It has obviously seen better days. Most people don’t even have box springs any more. Innerspring mattresses are one of the better inventions right up there with sliced bread and bagged salad.
Over the years, I have had various forms of bedding including traditional innerspring mattresses. I went through a waterbed phase which I liked because it was heated — great for cold mornings, but hard to leave when you had to go to work. My current bed has a Sleep Number mattress which is essentially an air mattress. Makes it very convenient when moving because there is no heavy mattress to carry. I also have an antique brass bed with a box spring in good condition, very comfortable. I have even slept in a sleeping bag on top of an air mattress in a tent as an adult. It was the deepest, soundest sleep I have ever had, but I think that had more to do with the natural surroundings than the mattress itself.
History
According to Wikipedia, the word mattress derives from the Arabic مَطْرَحٌ (maṭraḥ) which means "something thrown down" or "place where something is thrown down" and hence "mat, cushion." During the Crusades, Europeans adopted the Arabic method of sleeping on cushions on the floor, and the word materas eventually descended into Middle English through the romance languages.
The oldest known mattress dates to around 77,000 years ago. According Erin Wayman’s Dec. 14, 2011 article “The World’s Oldest Mattress” in Smithsonian magazine, this 77,000-year-old mattress was discovered in the Sibudu rock shelter in South Africa, a few miles from the Indian Ocean. Reporting in the journal Science, Lyn Wadley of the University of the Witwatersrand and colleagues say the three-foot-by-six-foot mattress — what they call bedding — consisted of compacted layers less than an inch thick and was probably used as both a sleeping and a work surface. The mattress also came with built-in pest controls: In addition to grasses and sedges, it was made from the stems and leaves of a type of laurel tree known as Cryptocarya woodii, whose aromatic leaves contain insecticides that kill mosquitoes.
The first hominid to try the ground as a bed might have been Homo erectus, starting 1.89 million years ago. The ability to control fire may have made this shift to the ground possible, argues Richard Wrangham, a biological anthropologist at Harvard University. In his book “Catching Fire: How Cooking Made Us Human,” he suggests that once hominids learned how to control fire they discovered they could sleep on the ground while the flames kept predators away. There’s no evidence in the paleontological record that hints at what type of bedding or ground nest Homo erectus used. But modern humans were certainly not the only hominids to construct “mattresses.” Neanderthals were also building grass beds, based on evidence from a cave site in Spain dating to between 53,000 and 39,000 years ago.
According to George Mackay Brown’s article “Skara Brae: The Discovery of the Village” at orkney jar.com, in the Neolithic village at Skara Brae in Orkney, Scotland, each house shares the same basic design — a large square room with a central fireplace, a bed on either side and a shelved dresser on the wall opposite the doorway. Radiocarbon dating in the early 1970s confirmed that the settlement dated from the late Neolithic — inhabited for around 600 years, between 3200 B.C. and 2200 B.C.
According to Rosella Lorenzi’s August 1, 2017 article “Fit for a King: Tut’s Camping Bed Was an Ancient Marvel” in Live Science, King Tutankhamun, the pharaoh who ruled Egypt more than 3,300 years ago, slept on the forerunner of our modern camping bed, according to a study presented at the latest international conference on the boy king in Cairo.
British archaeologist Howard Carter discovered the unique three-fold bed — made of lightweight hardwood — when he entered King Tut’s treasure-packed tomb in 1922.
The piece of furniture was smaller and sat lower to the ground than the other five regular beds found in the burial chamber of King Tut. Nevertheless, it featured a remarkable level of comfort, boasting a rather elegant design as well as a sophisticated technology, researchers have now found in the first study of the bed. Indeed, the bed folded up into a Z shape, thanks to an ingenious mechanism, the study showed.
Early mattresses contained a variety of natural materials including straw, feathers or horsehair. In the first half of the 20th century, a typical mattress sold in North America had an innerspring core and cotton batting or fiberfill. Modern mattresses usually contain either an innerspring core or materials such as latex, viscoelastic or other flexible polyurethane foams. Other fill components include insulator pads over the coils that prevent the bed's upholstery layers from cupping down into the innerspring, as well as polyester fiberfill in the bed's top upholstery layers. In 1899 James Marshall introduced the first individually wrapped pocketed spring coil mattress now commonly known as Marshall coils.
In North America the typical mattress sold today is an innerspring; however there is increasing interest in all-foam beds and so-called hybrid beds, which include both an innerspring and high-end foams such as viscoelastic or latex in the comfort layers. In Europe, polyurethane foam cores and latex cores have long been popular and make up a much larger proportion of the mattresses sold.
In North America the typical mattress sold today is an innerspring; however, there is increasing interest in all-foam beds and so-called hybrid beds, which include both an innerspring and high-end foams such as viscoelastic or latex in the comfort layers. In Europe, polyurethane foam cores and latex cores have long been popular and make up a much larger proportion of the mattresses sold.
The sizes of mattresses use non-numeric labels such as a "king" or "full," but are defined in inches. Historically most beds were "twins" or "doubles," but in the mid–1940s, larger mattresses were introduced by manufacturers. These were later standardized as "queen" and "king," and first made a significant impact on the market in the 1950s and 60s. Standard mattress depth ranges from the standard size of 9 inches to "high contour" of up to 13 inches. U.S. bed sizes usually have a length of either 74 or 80 inches, while UK bed sizes usually have a length of either 75 or 78 inches. Widths also differ between the U.S. and UK standards.
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.
There are four 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 mid-priced mattresses.
Bonnell springs are a knotted, round-top, hourglass-shaped steel wire coil. When laced together with cross wire helicals, these coils form the simplest innerspring unit, also referred to as a Bonnell unit.
- Offset coils are an hourglass type coil on which portions of the top and bottom convolutions have been flattened. In assembling the innerspring unit, these flat segments of wire are hinged together with helical wires. The hinging effect of the unit is designed to conform to body shape. LFK coils are an unknotted offset coil with a cylindrical or columnar shape.
- Continuous coils (the Leggett & Platt brand name is "Mira-coil") is an innerspring configuration in which the rows of coils are formed from a single piece of wire. They work in a hinging effect similar to that of offset coils.
- Marshall coils, also known as wrapped or encased coils or pocket springs, are thin-gauge, barrel-shaped, knot-less coils individually encased in fabric pockets—normally a fabric from man-made, non-woven fiber. Some manufacturers pre-compress these coils, which makes the mattress firmer and allows for motion separation between the sides of the bed. As the springs are not wired together, they work more or less independently; the weight on one spring does not affect its neighbors. More than half the consumers who participated in a survey had chosen to buy pocket spring mattresses.
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 flexible polyurethane foam — which includes convoluted "egg-crate" foam, viscoelastic foam, latex foam, felt, polyester fiber, cotton fiber, wool fiber and non-woven fiber pads. In Europe and North America, mattress makers have begun incorporating gel-infused foams, soft-solid gels layered over foam and poured gels in the top comfort layer of the bed.
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.
Foundation
There are three main types of foundation or bed base:
- A traditional box spring consists of a rigid frame containing extra heavy-duty springs. This foundation is often paired with an innerspring mattress, as it extends the life of the spring unit at the mattress's core.
- An all-wood foundation usually has seven or eight support slats disposed below paperboard or beaverboard. This foundation, variously called a "no-flex," "low-flex" or zero-deflection unit — as well as an "ortho box" — provides support similar to a platform foundation. All-wood foundations have become increasingly prevalent as U.S. mattress makers shifted to super-thick, one-sided mattresses.
- A grid-top foundation is a combination of steel and wood.
Typically, the measurements of a foundation will be about one to two inches shorter than the measurement of a mattress.
Fabric cover
Ticking is the protective fabric cover used to encase mattresses and foundations. It is usually designed to coordinate with the foundation border fabric and comes in a wide variety of colors and styles. Mattress fabrics can be knits, damask or printed wovens or inexpensive non-wovens. During the past decade, along with the rise in popularity of all-foam beds, stretchy knit ticking on the bed's top panel has become a standard look on both innerspring and foam beds. Most ticking is made with polyester yarns. More expensive mattress fabrics may contain a combination of polyester with rayon, cotton, silk, wool or other natural yarns.
Until the early 2000s, beds were normally upholstered with a single fabric. This was usually a damask ticking or for inexpensive bedsets, a non-woven fabric covering all surfaces of the mattress and foundation. Today's bedsets are covered with up to six different fabrics: A better quality circular knit or woven damask on the top panel — the bed's sleeping surface; a matching or contrasting [usually woven] fabric on the border of the mattress; a matching or contrasting [usually woven] fabric on the foundation side panels; a non-skid woven or non-woven fabric on the surface of the foundation and reverse side of the mattress; and a non-woven dust cover on the underside of the foundation. Some North American mattress producers are beginning to use furniture upholstery fabrics on the bed's borders giving beds a more European, home furnishings look.
Foam mattresses
All-foam mattresses use different weights and densities of petrochemical-based flexible polyurethane foams and viscoelastic foams or memory foam, and latex rubber foams. A number of mattress manufacturers have incorporated polyurethane and visco-elastic foams with a portion of plant-based content. All-foam mattresses are often paired with platform bases.
- Latex foam: Latex foam in mattresses is generally a blend of the latex of the Hevea brasiliensis tree and synthetic latex, which is derived from petrochemicals and other substances and fillers. There are, however, natural latex mattresses that leave out polyurethane-based chemicals. Latex foam is produced using either the Talalay or the Dunlop process.
Memory foam: Memory foam mattresses use conforming viscoelastic foam over firmer polyurethane base foam. Some innerspring mattresses have memory foam in their upholstery layer. Different feels and comfort levels are achieved by varying the thickness, weight and formulation of the viscoelastic foams and the base foams. Latex and memory foam mattresses each provide a unique feel. This type of mattress is good at relieving pressure on painful joints. Many memory foam mattresses are more expensive than standard spring mattresses. Memory foam is affected by temperature. In a cool bedroom, a memory foam mattress will feel firmer than it does in a warm bedroom. Memory softens and conforms to the sleeper in response to body temperature and body weight. Traditional memory foam molds to the body creating a depression the sleeper must roll out of when changing sleep positions. Mattress manufacturers have responded to this issue by using "faster response" memory foams. They spring back more quickly when the sleeper moves. Foam mattresses are also known to generally "sleep warmer" than innerspring mattresses. Mattress makers have addressed the issue with "open-cell" memory foams, pinhole-cored memory foam, gel-infused memory foams, channel-cut foam cores, reticulated foam support layers and other technologies to improve air circulation through all-foam beds.
- High density foam: Similar to memory foam mattresses, a high density foam mattress uses a more compact foam typically made from polyurethane. This kind of foam is made largely from open cells that are packed together tightly. High density foam mattresses offer comfort and longevity because they are more dense than a traditional foam mattress. High density foam mattresses that have an innerspring system last even longer and eliminate mattress sagging.
Bladder mattresses
Mattresses can also be made from bladders of some fluid, notably water or air. These date to antiquity — goatskin bladders filled with water were used in Persia at least as early as 3600 BCE — and gained increased popularity in the 20th century with improved manufacturing.
· Air mattress: 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 to high-end luxury beds. Air mattresses designed for typical bedroom use cost about the same as innerspring mattresses with comparable features. Air bladder construction varies from a simple polyethylene bag to internally baffled, multiple chambers of latex (vulcanized rubber) or vinyl with bonded cotton exteriors. Mattresses may have a layer of foam above the air chambers for added cushioning and may be enclosed in a cover. Some such beds are termed soft-sided air beds. Permanent use adjustable firmness "airbeds" became popular particularly after market leader Select Comfort (Sleep Number) began a major marketing campaign around 2001. The original airbed was manufactured by Comfortaire in 1981, which was later purchased by Select Comfort. There are several other manufacturers. Some allow independent adjustment of each side of the bed. They are made in a variety of models from basic, no-frills ones that measure about seven inches in height, to high-profile, 15-inch tall hybrids that contain several types of foam, pillow tops and digital pumps with memory for individual pressure settings. Studies suggest that adjustable-firmness beds are better for back pain. Adjustable-firmness mattresses for medical use have special control mechanisms. In the 1990s self-adjusting air beds that automatically change their pressure periodically — or inflate and deflate several air chambers alternately — were introduced. The intention of these periodic changes is to reduce problems with decubitus ulcers or bed sores, though as of 2008 the effectiveness of these techniques was still being researched.
Air mattresses for camping are available which are filled with foam which itself provides little support but expands when the air valve is opened allowing air to enter, so the mattress nearly inflates by itself. This is especially useful for campers who carry their equipment as — unlike with normal air mattresses — no pump is needed for inflating. Available brands include Aerobed, Coleman, Therm-a-Rest and others. The U.S. Consumer Product Safety Commission advises consumers not to let infants sleep on air mattresses. This is motivated by reports of deaths of mostly infants younger than 8 months of age who were placed to sleep on air mattresses, and either suffocated in a face-down position on an air mattress or died due to suffocation after falling into gaps between the mattress and bed frame, or the mattress and adjacent furniture or wall.
- Waterbeds: A waterbed is a mattress with water in its interior instead of metal coils or air. Waterbeds can be lined with different layers of fiber to achieve the level of firmness the user desires. Waterbeds are well known for providing support to the spine and other body parts, similar to the other mattress types. There are several options of support which range up to 100% waveless, where the user does not notice that they are lying upon a waterbed.
Lifespan
The term mattress lifespan refers to the duration in which all types of mattress can retain their original support and comfort. Mattresses deteriorate over time, and the lifespan of a mattress depends on a variety of factors, notably materials, manufacturing quality, care and the rigorousness of use. A poor-quality foam comfort layer can deteriorate noticeably in one year, while a quality latex core can last 20 years or more; innerspring cores typically last around 10 years. The comfort layer is almost invariably the first area to fail, which is why mattresses are often double-sided, to extend the lifespan. A separate topper may be used instead of or in addition to a comfort layer, which reduces wear and is replaceable without replacing the entire mattress. The majority of high-end mattresses have a lifespan of between 7–10 years, but they can last beyond 10 years, depending on the level of care.
In the United States, mattress warranties are typically for 10 years or 20 years — sometimes 25 years — though this specifically addresses manufacturing defects and faster-than-normal deterioration, not expected deterioration with time. In the United States, as of 2008, there is a general expectation that mattresses should last about 10 years, and this is the average number of years Americans keep mattresses, though this varies by age group. This expectation is based on a number of factors, including sales pitches; the expectation that mattresses will last the length of their warranty, hence 10 years or 20 years, accordingly; and comparison with other household items.
The mattress replacement cycle is a key driver of income and profits for the mattress industry — a 5-year replacement cycle yields double the sales of a 10-year replacement cycle, for instance — so the mattress industry has a financial incentive to shorten the replacement cycle. Notably, the International Sleep Products Association established the Better Sleep Council in 1979 with the stated goal to "shorten the mattress replacement cycle," in addition to encouraging people to "invest in better bedding."
An industry-funded 2006 study by researchers at Oklahoma State University (funded by the BSC) of 59 people with poor sleep who received free new replacement mattresses for their existing mattresses five years or older — average age 9.5 years — found improved sleep, particularly when the existing mattresses were cheap. A follow-up paper by some of the same authors with additional statistical analysis reinforced these conclusions. The BSC has subsequently cited this study in the ISPA-published news magazine for mattress manufacturers, BedTimes, to advocate a more frequent replacement cycle, specifically to "consider replacing a mattress every five to seven years;" the recommendation is based largely on this study.
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