A mattress will weigh somewhat more after several years. It may even amount to several pounds. And what is the matter that is added to the mattress? Much of it is dust mites, up to a million of them in a single bed. But more than the mites, it is also their discarded bodies and excremet. In many cases, mattress can also absorb various bodily fluids, such as urine, semen, and sweat. Not all of the fluid will soak through sheets, but some will. Discarded skin cells are small enough that some will work their way through layers of cloth and into your mattress.
You may have heard that an ordinary mattress can weigh twice as much after eight or ten years. While that’s not true, you may be alarmed to discover the actual truth.