In the late 1940’s and 1950’s, our parents and grandparents were celebrating the end of World War II and a new era of freedom and security. Having lived through not only the war but also the Great Depression, they wanted things that would last. Whether they were looking for a car, a sofa, a refrigerator, or a bed, customers demanded durability.
Mattress manufacturers were aware of this demand, so they set about making mattresses that would last a really long time and focused their advertising on longevity.
The physics of making a durable mattress at the time limited how much softness and comfort they could achieve. Just as brick and steel will outlast wood and glass, harder and denser materials will outlast softer, lighter materials. So, with the focus on durability, manufacturers had to use harder and denser materials, which resulted in firmer mattresses (see What Makes a Durable Mattress).
Sales messages went along with the materials, and manufacturers did a fantastic job of promoting the notion that “firmer is better”. That’s why even today, many people think that a firmer mattress that offers more support is better than a softer mattress that offers more pressure relief. (The truth is that you need a combination of both.) We’d like to think there was more truth in advertising in those days, but the firmer = better trend may have been more about what was easiest to manufacture, rather than what would encourage the most comfortable sleep.
While promoting the “firmer is better” belief, manufacturers simultaneously began making mattresses feel softer by putting springs beneath them. Springs come in several basic forms. Most often, they are “box springs” that match the mattress in size and appearance. Others are “spring beds” that feature a steel grid with springs attached around the edges to give the bed a softer “bounce”.
Most people have tried a spring bed at some point in their lives—they’re often found in college dormitories or other institutional settings. These beds or bases usually have very firm mattresses on top. The mattresses feel a little softer because of the flexible base.
A high-quality mattress such as a natural latex mattress will not perform well on a spring-and-steel bed, because a latex mattress has a soft core. When it sinks into a spring base or box spring, it can hammock or sag.
A conforming design, such as a latex mattress, is intended to cushion your body’s weight while the mattress itself is supported by a rigid base, such as a foundation or platform bed. The rigid foundation or platform allows for a softer surface for pressure relief, and denser layers below for optimal back support. Softer on top and supportive underneath is a good general guide for what to look for in a healthful mattress.