Memory foam consists of polyurethane and additional chemicals. It is also called visco-elastic polyurethane foam. A low density foam molds as per the shape of the body very fast, and is pressure-sensitive. A high density foam reacts to body heat. It molds as per the shape of a warm body in a few minutes. If a hand is pressed into the foam and then removed, a distinct impression is left on the foam.
Memory foam mattresses were developed by NASA. The objective was to offer relief for astronauts undergoing G-forces. These mattresses respond to the heat of the body and mold around it. The pressure points are relieved and blood circulation is improved. The excellent therapeutic cushioning and support enables a good night's sleep.
Such a mattress has several advantages, like full body pressure relief, reduced tossing and turning, lower and mid back support, deep REM sleep, relief of joint and neck pain, reduced skin temperature, increased body circulation, anti-mite and anti-allergy, proper spinal alignment and no motion transfer.
The outer cover can be removed, hand washed in cold water with mild soap and dried on low setting. It should not be bleached. These mattresses are shipped vacuum sealed in space bags. When this bag is cut, the mattress expands to the full size in about 24 hours. Some of these mattresses have a Bragada's box spring which is better than the wood foundations. The high performance base foam has five inches of superior support foam. The visco-elastic material has two inches of NASA developed memory foam material. The exclusive velour cover is breathable so that air circulates the body and sweating or overheating does not happen.
It is a piece of visco-elastic foam. This is placed on top of the mattress and is one or two inches thick. It provides the support and comfort of memory foam without investing in a full scale mattress. Some toppers have patented heat reduction channels which provide superior air circulation and a variation in firmness. The side of the topper having the air channels provides a softer feel than the flat side. Memory foam of density 5 lb is more supportive than that of 4 lb density.
After some use, the foam loses its bounce, and hence, must be turned periodically. Thinner pads are used to overcome allergy or for hygiene. Toppers are made to suit all standard bed sizes. These increase the performance of any mattress. However, it can't help an old one. For example, if a mattress is thirty years old, sagging and spring poking cannot be overcome using a topper. However, if there is a new mattress and the owner would want to enjoy the touch of a memory foam, a topper is a very good option.
Memory foam pillows may be very firm and rigid, or soft and spongy. If a 4 lb density foam is used in the pillow, it is not as temperature sensitive as other foams. It retains the comfortable feel for a large range of temperatures. Also, it does not harden below 70 degrees. The standard size is 21 inches wide, 14 inches deep and 5 inches tall at the top of the curve. Such a size is meant for those having weight of 120 to 180 pounds and 5 feet 2 inches to 6 feet tall.