A little history of memory foam mattresses
Memory foam mattresses are made, as you've probably heard many times, from a special foam developed by NASA as a means of helping astronauts deal with the enormous g-forces of liftoff. What is not generally known is that the original memory foam developed in the 70's was never actually used in a space flight¡ªnot at first. But it proved a boon to the medical industry because memory foam mattresses helped prevent bedsores in bedridden patients.
How memory foam mattresses work
Another reason why memory foam mattresses are so comfortable is that they are an open cell foam. Closed-cell foam is like those thin sleeping pads backpackers sometimes carry. The closed cells trap air in bubbles so that a relatively thin piece of foam is very springy. But in a larger memory foam mattress the air can move between cells, which ultimately makes iteasier to distribute the weight of the sleeper and create a more comfortable sleep.
What should I look for in selecting a memory foam mattress?
When selecting a memory foam mattress, bear in mind that many memory foam mattresses are not just a single hunk of foam, but are built up of layers of foam. These layers that make up a memory foam bed are of different densities and will combine to affect the type of sleeping experience you have. But whatever you do, buy from a reputable dealer and make sure you are satisfied with their return policy, just in case the mattress doesn't suit you.