Memory Foam Mattresses are being used all over the world, not only for their comfort but also for all the health benefits they provide. The first memory foam was developed for NASA around the 70's for their space program, though it was never used. Memory foam is pressure sensitive, or temperature sensitive polyurethane foam which has the ability to compress, but then gradually return to its original shape. Therefore memory foam does not place nearly the same resistance on the joints as springs, air, and other materials that bounce back more rapidly. This invention has created a real hit among young and old alike. The Memory Foam Mattress has become the fastest growing segment in the mattress industry. Memory Foam Mattresses have the ability to spread pressure over a greater surface area. These mattresses are now prescribed by doctors as well, for people having difficulty sleeping and other health problems like backache, as they can help to reduce pressure points. There are many different companies now that make these mattresses, though not all memory foams are created equal. So don't try to compromise on the price; instead of getting those really inexpensive ones and regretting later, it's better to pay a little more and be assured of the quality you are getting. The cheap memory foam mattresses are generally made of either low density memory foam or layered with other cheaper foam products. They may not give the same comfort as higher density mattresses and will wear out relatively fast. Memory Foam Mattresses come in different types. 4 lb density ones are the most popular as they are very high quality products and can last for a good amount of time - about 3 - 5 years. 3 - 3.5 lb density memory foam mattresses are cheaper than the 4 lb ones. If you are willing to pay more, you can also get 5.3 lb density, which are of very high quality. This density mattress is heavier, more temperature sensitive, usually stiffer, and bounces back more slowly. No matter which one you buy, you need to be careful about what foam it has in it. See that the cheap fillers are not used for your mattress. You should thoroughly research the company you are planning to get your Memory Foam Mattress from. You should also check about the durability. Some may feel great in the beginning but may break down quickly. You should try and be safe by sticking to formulations that have been time tested, and not blindly rely on any new formulations. A good Memory Foam Mattress is something you can invest in and you will definitely not regret it. You have to use it to believe it. So drive away those sleepless and uncomfortable nights, and get yourself one today!