The Truths & Myths About Memory Foam Mattresses

History

• In the 1970s, NASA scientists were tasked with developing a foam for spacecraft seats that would protect astronauts from the G-forces of liftoffs and landings. NASA released the patent for the foam into the public domain in the 1980s. A Swedish company evolved that original formula into today's memory foam. It used the foam initially for hospital bed mattresses. Then it expanded its product line to include mattresses for consumers. An American businessman joined the Swedes in the 1990s to produce memory foam products under the Tempur-Pedic brand name.

Properties

• Memory foam's open-celled, temperature-sensitive density is measured in pounds per cubic foot ranging from 2.5 to 8 lbs. The denser the foam, the more heat it traps. The warmth and pressure of a body causes the foam to spread out and mold itself around the body on top of it. When the pressure and warmth are removed, the rebound property, or Indentation Force Deflection, returns the foam to its original shape.

Myths

• Memory foam mattresses are marketed as outlasting conventional mattresses, but the durability of a memory foam mattress depends on the density of the foam used to make it. If mattresses are made of foams of less than 3 lbs. per cubic foot of density, they can quickly lose their "memory" ability. The mattresses are also marketed as being dust-mite resistant. The dense composition of all foam mattresses, memory foam or not, makes it difficult for the parasites to feed and propagate. But no foam mattress is completely free of dust mites.

Truths

• The marketing of memory foam mattresses on the basis of their superior ability to support a body by conforming to the sleeper, thus relieving pressure points, does appear to be born out by independent research. The dense composition of the mattress also allows bedmates to move without disturbing each other by isolating movement of the mattress. Some consumer reviews describe relief from pain, both during and after sleeping on the bed.

Warnings

• Memory foam mattresses can present an odor problem when new, which is caused by a process called "out-gassing." This is caused by materials that are used to manufacture the mattresses. If they are aired out for a day or two when new, the smell usually disappears. The lack of breathability of the dense foam has led to consumer complaints about the mattresses being too warm in summer and too hard when temperatures are low.