It’s a common misconception among the public that viscoelastic is a trademarked brand name. Not true. It’s a scientific term that describes materials with two combined properties. Memory foam is viscoelastic because it changes shape (viscosity) and stretches (elasticity) at the same time. All this sounds quite boring on paper and doesn’t begin to describe the wonderful experience of sleeping on a bed that’s made specifically with these qualities.

Visco elastic foam dates back to 1966, when two engineers under contract to NASA invented it to make flight cushions safer. It was never actually put into that service, and in the early 1980s, NASA released the trademark to the public domain. The Swedish company, Fagerdala World Foams, put it into production and in 1991 released a mattress product dubbed the Tempur Pedic Swedish Mattress. This bed quickly found favor in hospitals and for the home care of bedridden patients, who found that it made them much less prone to bed sores. Tempur Pedic mattresses were so expensive that they never sold in large quantities, although the public was quite familiar with them due to an aggressive infomercial campaign by the manufacturer.

What’s it like to sleep on a viscoelastic mattress? In a word, heavenly. It combines the support features of a firm bed with the cushiness of a soft one. Users report that sleeping on a vicso elastic memory foam mattress is a completely different experience than sleeping in a conventional bed. Because the foam is temperature sensitive (which explains the brand name Tempur-Pedic), it softens and molds itself to the exact shape of your body as soon as you settle in for the night. But although it’s incredibly soft, softer than any bed you’ve ever slept on in your life, it also provides great support, no matter what your body weight. If you suffer from back pain, it might be just what the doctor ordered. If you have health problems and have to spend a lot of time in bed, you’ll be a lot more comfortable than you would be on a conventional innerspring.

Viscoelastic foam mattresses can be rated by several different methods, but for consumers, density measured in pounds of material per cubic foot is the best rule of thumb. This material is quite heavy, so densities of 5 lbs. per CF are not uncommon, and are the sign of a top quality unit. Along with this high density comes a high price tag, so most consumer level units are 1 to 3 lbs. per CF. High density foam feels much firmer and compresses more slowly than its low-density counterpart.

Unfortunately, most retailers prefer to measure their merchandise by thickness rather than density, such as a 3 inch visco elastic memory foam mattress. This isn’t the best way, because density and thickness are two separate qualities, but thickness will affect your quality of sleep. If it’s too thin, you won’t get the full luxurious effect. If it’s too thick, it will also be too soft and won’t give your body good support, unless it’s a top-end 5 lbs. per CF model. The thicker and denser the foam, the higher the price tag, so aim for a 3” visco elastic mattress with as much density as you can afford.

Much has been made of viscoelastic foam health hazards. Studies in this area have been inconclusive so far. These beds are made of polyurethane, which gives off a distinct odor that bothers some people. The smell is worse when the unit is new, so give it time to fade if you like the sleep experience otherwise. Polyurethane is also flammable, so the fire retardant chemicals PBDE is added during the manufacturing process to comply with United States federal law. These chemicals may possibly be of more concern than the material itself. However, visco elastic mattresses are more resistant to mold, mildew, and dust mites than conventional innerspring models, so people with allergies and asthma may find that their symptoms decrease.

Serta got in on the visco elastic trend several years ago and now offers a full line of products to meet the needs of the most demanding consumers. The Serta Vera Wang memory foam mattress and the Serta True Response are only two of the models offered by this manufacturer.

All in all, it’s a sleep experience that you won’t find anywhere else.