I’m 5’8" 160, mostly side sleeper. Lately I’ve tried several 3-zone and 7-zone latex mattresses, all made from Mountain Top dunlop, all but one 100% synthetic. I’ve noticed an odd phenomenon: while on my side, my hips/pelvis often seem to get pushed up, so my lower back is flexed up at the sacrum relative to my spine. The degree of bend depends on the firmness of the mattress, but I’m wondering if my body just doesn’t fit the “default” zoning built into these layers and whether I need to avoid zoning altogether. A Talalay topper or top layer would provide an even, unzoned surface, right?
There are several variables that will determine whether a particular zoning scheme is suitable for a particular person.
The first part of successful zoning is the number of zones, the width of each zoned section, and how well they match up or “fit” with the areas of the body and sleeping positions that need different firmness levels to maintain best alignment. For those that can benefit from zoning … the two most important zoning sections are a firmer middle section for the lower torso and pelvic area and a softer upper section for the upper body and shoulders. Most of the body weight is concentrated in the lower torso and pelvis and a firmer section in the middle can benefit many people and prevent the pelvis from sinking down too far which in turn can tilt or twist the pelvis and affect the curve and alignment of the lumbar spine. The pelvis is heavier but is also often narrower than the shoulders (more in men than in women) so “stopping” it from sinking down too much and tilting can often help alignment. The shoulders and upper body are generally wider (particularly in men) and lighter so a softer upper third zone can help the shoulders to sink in more deeply for better pressure relief and alignment. In a 3 zone system most people would fit this type of zoning.
In zoning schemes with more zones … then a firmer section under the recessed area of the lumbar can also be useful so you can have a softer shoulder section, a firmer pelvic section, and a section under the recessed part of the lumbar curve or waist that is a little firmer yet under the inward curve of the lumbar (on the back) or the waist (on the side). These would be a “standard” zoning scheme that would generally fit the most people. A firmer section under the knees to help keep them from bending sideways (on the side) or keep them slightly bent (on the back) can also be helpful. In general terms the recessed spaces of the body can benefit from firmer materials and the protruding pressure points can benefit from softer material. Other less critical areas that can benefit from zoning would be some of the other recessed gaps or wider areas in the body profile such as the space between the buttocks and the thighs, the thighs, the neck and cervical spine, and under the heels which for some people can be a pressure point. With more and narrower zones the odds become higher that some people may not line up with the zones as well (see post #18 here).
The second part of a successful zoning scheme is the firmness differential between the zones. The ideal variations can vary widely between people depending on their body proportions and shape (see here), sleeping positions, and weight distribution which all affect how evenly they will sink into a mattress.
Suitable zoning that matches a person in terms of the width of the zones and the firmness variations can be very helpful both for pressure relief and alignment. Zoning that isn’t suitable in one way or another for a particular person can be detrimental. In most cases … a 3 zone system can be helpful but with more complex zoning schemes or narrower zones then it can increase the odds that the zoning isn’t the best match for a particular person and in some cases with some people and body types or some types of materials then no zoning at all can actually be the best option. The goal is always good alignment and pressure relief in all your sleeping positions and if zoning can help this then it can be a great idea but if it doesn’t then the “wrong” zoning can make things worse. Materials with a higher compression modulus (how quickly a material becomes firmer with deeper compression) such as latex are less likely to need zoning because they can “stop” the heavier parts from sinking in too far as they compress more deeply even without zoning so in a sense they have a form of “built in” zoning.
