The most important factor for selecting a mattress is personal comfort. If a bed feels good, then it will largely contribute to better sleep and a healthful sleeping position. However, many shoppers go about searching for a new mattress with preconceived notions about what they "should" be looking for.
The medical community often gives confusing advice. Some doctors say a firm mattress is better for support and some say a softer mattress is better. But this advice is contradictory and too simplistic to be helpful. Firmness is not directly related to proper support or comfort, so the advice is not as helpful as it could be. Good advice would say to get a mattress that:
Twin Firm Mattress
Reduces pressure points - evenly distributes pressure across the surface of your body, not just the heavy parts of your body.Keeps your spine in a neutral position - supports your inward body curves (neck, lower back) as well as your outward body curves (hips, shoulders), maintaining a natural body position.Feels comfortable to you - Your body is smart; It knows that personal comfort will naturally contribute to healthful sleep and a natural body position. At the top of a long list of health benefits for latex and memory foam mattresses is their ability to reduce pressure points and give proper support. Foam beds contour to the shape of your body, reducing pressure points better than almost any other type of sleep surface.
Foam mattresses come in varying firmness levels based upon the firmness of the foam used to make the mattress and how the bed is constructed. Both latex and memory foam mattresses are made up from 2 or more layers of foam. The top layer is soft, contouring to your body and offering gentle support. The lower layer or layers provide firm support, maintaining your healthful body position.
How Foam Firmness and Support is Measured Foam firmness is measured in units called ILD's (Initial Load Deflection). Most latex and memory foam mattresses have top layers from 10 - 20 ILD. Foam ILD is a measure (in pounds) of the resistance foam offers when a large, flat plate is pushed into a block of foam 25% of its total depth. In other words, it measure how firm/soft the surface of a foam block feels. Higher ILD is firmer and lower ILD is softer.
The support of a foam bed is expressed as "support value," and is derived from 2 numbers: 25ILD and 65ILD. 25ILD measures the resistance at 25% of the depth of foam and 65ILD measures the resistance at 65% of the depth of a piece of foam. By dividing 25ILD into 65ILD, you get the support value. Support value tells you how well a piece of foam will support you when you lay down on it. Will it keep your spine in a neutral position, or will it completely compress and let you hips sink too far into the mattress and bump on the harder base layers?
Buy What You Like It is becoming more common for retailers to have ILD firmness values available at the retail level. This is helpful when considering the beds from one manufacturer. But there is not an apples to apples to comparison between one manufacturer and another. Support value is not available at the retail level, and again, it would not help compare beds between different makers, so it's not a good comparison tool.
The important thing to understand is that both soft and firm latex or memory foam mattresses are capable of providing optimal support. Foam firmness level is not a direct indicator of support. The one you chose should make you look forward to going to sleep at night.