Hi Lew,
This is what I noticed in your experiences (that the issues develop after a few months or during the “break in” period of the mattress) which was the reason for my comments. Foams will generally go through three stages of softening and breakdown. First is the initial softening which is the break in period. Next is the more gradual softening over a much longer period of time. Finally there is the last stage where the material itself breaks down and loses height. To some degree the last two stages overlap.
When there is a pattern of experience that seems to conflict with “normal” experience and someone’s experiences on several mattresses where this “shouldn’t” be happening is different from the norm … then it’s usually a good idea to look at other more “uncommon” solutions other than the normal response or softening of the material itself.
Sometimes this may have less to do with the mattress and be more about changes in the body or lifestyle changes (or the accumulated effect of both over time) as we inevitably “age” and our bodies lose flexibility or the ability to “adapt” to smaller changes as easily. Post #1 here has some good information about this.
It’s also very difficult to accurately identify the underlying cause behind certain symptoms because bodies can be so complex and a cause in one area of the body can led to symptoms in another (especially with backs).
To the degree though that any of your “symptoms” are caused by alignment issues (either vertical or rotational alignment) … then there are three main areas of the body that are part of good alignment. These are the pelvis, the recessed part of the lumbar, and the shoulders. The head and neck are also important and can have an effect on other parts of the spine but this is more about the pillow.
Pelvic tilt is the single biggest factor in controlling the alignment of the lumbar spine and if the pelvis sinks down too far or not enough then the pelvis will tilt and cause alignment issues and lower back pain or discomfort. In general the area under the pelvis needs to be firmer than the area under the shoulders so that you sink into a mattress in good alignment without tilting the pelvis. The second area that contributes to lower back alignment is the firmness of the materials under the recessed part of the lumbar and for more difficult body types such as those you are less evenly proportioned, carry more weight around the middle, or have a more curvy or athletic body type (wider shoulders or wider hips with a narrower waist or bigger lumbar curve) then there is usually a benefit with having materials under this area of the body that are firmer than the pelvic zone. This can help prevent the lumbar from sagging. One of the difficulties when talking about “lumbar support” is knowing whether it’s the lower lumbar where it connects to the pelvis or the upper lumbar where it curves inwards. Both can have separate issues even though they are interconnected. The “ideal” alignment is a lumbar curve that is close to when we are standing up with good posture but slightly less curved because when we are lying down the spine is under less vertical stress and is slightly less curved.
If a zoning system doesn’t “match” your specific body type and weight distribution it can either help less or it can sometimes be detrimental. The benefit of custom zoning systems is that they can be customized to the specific needs of each person although this can take some trial and error to get right.
This is a very unusual “symptom” and could be connected to the normal break in period of a foam where the parts you don’t sleep on are firmer than the parts you sleep in more often but it would take a very sensitive person to notice this type of side to side alignment issue if you are flat on your back to the degree that half of their body is higher than the other and this is causing an issue. It would also be less with latex than with other foams. If it’s from foam softening it would be self correcting when all the parts of your mattress have gone through their initial break in period and are more even in terms of softness.
If this is a long term issue that continues after the initial break in period then I would also look for alternative causes that may be more connected to something else including issues that have more to do with your physiology or a lack of flexibility on one side of your body where your muscles or joints are somehow contributing to the side to side or rotational alignment issues. It could also be connected to the relative range of motion on each side of your body (you can twist more easily in one direction than another) so that once you sink in past a certain point one side will continue to sink in more than the other because of muscle or joint tension on one side of your body (such as the hip flexors). It could also be connected to some muscle weakness in the abdominals or other core body muscles that hold your body in good rotational alignment. You’re right that the flobeds design in only zoned from top to bottom and not from side to side so it wouldn’t be a solution for this.
It would be interesting to know the exact positioning of the boards and whether they are placed specifically to only affect one side of your body or whether the positioning affects both sides of the body (which could be a “pointer” to what is happening). I’ve talked with two people I know who are more more technically oriented or “geeky” about mattresses, physiology, and ergonomics and biomechanics and I’ll have one more conversation tomorrow to see if any of them have any insights but so far they agree that the odds are higher that side to side rotational issues of this type when you are flat on your back are more likely to be connected to physiology or musculature or joint issues than to the mattress itself.
Phoenix