In a mattress design two things critical – intensity of peak pressure at the pressure points and spinal alignment. These two factors are inter-related, and in a regular mattress, often one is gained at the expense of the other.
The weight of the human body is not uniform throughout the length of the torso. Weight is concentrated in the shoulder and hip areas and when we lie down on a mattress. The pressure of the mattress on our body is maximised in these two areas, commonly known as pressure points. A pressure above 30 mm Hg on any part of our body can cause stoppage of blood flow to that area which could lead to permanent soft tissue damage if exposed to this condition for a long time.
It is not possible to limit the peak pressure at the pressure points below 30 mm Hg because the average weight of a human body is simply too much as compared to the body’s contact area with the mattress through which the weight of the body has to pass. Fortunately our body’s internal mechanism is such that even in a sleep state, it senses the pressure points and before any permanent damage is done, it makes us turn and change position. How many times we turn and change position during the night depends primarily on the intensity of peak pressure at the pressure points.
Our body senses the pressure points as soon as we lie down on a mattress and the softer the mattress, the less is the intensity of pressure at the pressure points, the more is the feeling of comfort.
The second and equally important criteria in mattress design is the alignment of the spinal cord when we lie down on a mattress. Ideally our spine should be in its natural position when we lie down on a mattress, i.e., our spine should be perfectly horizontal in a side sleeping position. Any deviation from horizontal position will cause spinal distortion. Spinal distortion is measured by the angle between the tangent lines at the two ends of the spine. Any distortion beyond 5 degrees, could lead to chronic back pain if exposed to this condition for extended periods of time.
In a very soft mattress, though it feels comfortable due to reduced peak pressure, the two heavier ends of the spine, the shoulder and the hip areas sink into the mattress causing the spine to arch upwards as shown in the picture below.
Medium or Firm Mattress
Sensing a lack of proper support for our body with a soft mattress, we tend to choose a firm mattress which is even worse. Not only does it not prevent spinal distortion, it also causes higher peak pressures at the pressure points. Higher pressure at the shoulder and hip areas as compared to the mid-section of the trunk tends to bend the spine downwards as shown in the picture. In absence of any other alternative, most chiropractors tend to recommend a medium firm mattress. However, the term medium is highly subjective. What feels medium firm to a 300 Lbs. male will probably feel very firm to a 120 Lbs. female. As well, medium firm mattresses from different manufactures vary widely in firmness.
The Nuage made to body measure solution
All our Made to body measure mattresses are provided with special layer of foam, called pressure equalization layer which goes in between the conventional base layer and comfort layer. Pressure equalization layer transfers part of the contact pressure of the mattress from high pressure areas at the shoulder and hip areas to the low pressure area at the middle of the torso, thereby reducing the peak pressure intensity by as much as 25%. More or less equal pressure throughout length of the torso considerably reduces spinal distortion; well within the safe limit of +/- 5 degrees