The amount of spring in the sofa bed mattress less than normal , compared with elastic enough , people lying on top of sleeping for many years , the bones do not get enough to relax, not conducive to sleep . Therefore , it is best to buy their own bed , sofa bed used as a supplement . May be due to this reason , the current specialized production sofa bed very few manufacturers , most of the furniture brand sofa bed just as is their & ldquo ;.