I recently took delivery of the PLB Nutrition (discussed on another thread). I tried it out in the store for well over an hour, and also tried out the other PLB models. After four nights, things are not turning out as I had hoped, and am hoping you can provide some feedback.
The problem seems to be that the bed may be both too firm AND too soft, if that makes sense. When I lay on the mattress, after a while I begin to feel a hard pushing sensation into my lower back lumbar. I wake up with a back/muscle ache feeling in that lower lumbar area - something I generally have not experienced in the past.
When on my side, I can feel this pushing sensation into my upper ribs, under the shoulder. It is a hard pushing sensation and definitely not pleasant.
I’m not sure why I am experiencing this push sensation at home but did not experience it at the store.
Last night, I tossed a memory foam topper on the mattress and slept on that. In terms of the push feel, that solved the problem. I slept well. However, I think this solution renders the bed way too soft for my build. I believe that my behind sinks right through the two inch topper and the two inches of the 19 ILD of the bed (stopping at the 28 ILD mid layer), rendering the spine improperly aligned. Besides, I didn’t spend all this money for latex to end up sleeping on top of memory foam, which I don’t particularly care for. I certainly enjoyed the plush feel of this setup, I just don’t think sinking so far is good long term.
Any thoughts on this one? Is this “push” feel (without the memory foam) something that can be overcome? I can return this bed (albeit with a hefty restocking fee), so I am not completely stuck… but it is an outcome I’d rather avoid.
What I believe you are experiencing is phenomenon that is often … mistakenly … referred to as “pushback”. It is part of the most desirable qualities of both latex and HR polyfoam and would also be similar to lying directly on some types of pocket coils. For some however … it is also part of why they don’t like latex. Here’s what I believe is happening.
First of all though for reference … I’ll post your “specs” from an earlier post and the specs of the Nutrition.
With a material that has a high compression modulus (ability to get firmer faster with deeper compression) and a high resilience (ability to store and return energy) … it becomes possible to choose an ILD (tested at 25% compression only) that is softer and provides better pressure relief because as you sink into it it will “catch up” to other foams with a lower compression modulus in terms of its deeper firmness levels and still provide deeper support. This gives materials like this which also have a high “point elasticity” (the ability to compress in a local area without affecting the surrounding area as much) a unique ability to spread out the body weight over the surface of the body and relieve pressure on the more “protuding” parts. They do this by allowing the more protuding parts to sink into the mattress until the wider more recessed parts also begin to bear some of the body weight (are being held up by the higher resilience and compression modulus foam under them). If a polyfoam of the same ILD but lower compression modulus is used on the top of a mattress … then someone who sinks into the mattress to a similar depth will not bear as much weight (have less support) under some areas of the body that are more recessed or flatter.
This ability is why latex, HR foams and similar materials like some pocket springs are so desirable in a mattress and the target for most manufacturers. While they are the “ideal” that most manufacturers strive for, it also comes with a down side … particularly in a mattress where people sink in a little further and the foam under the recessed parts is bearing more of the weight than they are used to with lower quality foam with a lower compression modulus. If you had for example the same ILD’s of lower quality polyfoam in your mattress … more of your weight would be supported by your heavier parts and less of it would be supported by your recessed parts. In particular this affects the lumbar curve and the flatter torso once the shoulders have sunk into the mattress.
In effect … your mattress is allowing you to sink in enough that some parts of your body are bearing weight that are not used to it. For those who need or like this increased support under the lumbar curve … they will call this “support” and if they are comfortable with this … they will feel like they are sleeping in a weightless position or “sleeping on a cloud”. For those who aren’t used to this increased load on parts that have never felt it before … they will call it “pushback” … and for a time it may be uncomfortable. In other words … it is often a side effect of the type of sleeping surface that people are used to and the sensitivity of certain areas of the body to bearing weight.
The reason that “pushback” is not an “accurate” term is because when a body omes to rest on a mattress and the forces are in “equilibrium” the direction of the force is not what is felt … it is the weight being supported along the surface of the body that is felt. This is true with all materials.
So in effect … with the ILD and thickness of the foam in the Nature … you are sinking in a little deeper and while you are likely still in alignment … the pressure has be spread out to areas of your body surface that are not used to it.
So on to what can be done.
The first thing that can be done of course is to re-educate your body to bear weight more evenly and allow the lumbar curve to become accustomed to the increased support. This may take some weeks but if you do adjust to this … you likely won’t want to sleep in any other way after this. Spreading the pressure over a larger surface area really can lead to the feeling of “sleeping weightless” if every area of the body is bearing a load that is below it’s perception of pressure.
The second way is to “lower” the support under the lumbar curve and “increase” the support under the pelvis and shoulders (reducing pressure relief in these areas slightly). This is done by decreasing the amount you are “sinking in” to the mattress as a whole so that the recessed areas are not bearing as much weight.
In the PLB … they use a very elastic and high quality knit ticking which has no quilting in it. This allows you to sink in more deeply into the softer latex and distribute pressure better (bear in mind that for you with a higher weight … 28 ILD still qualifies as “softer”). A thicker layer of wool on the surface will reduce the amount the more “protuding parts” are sinking in and provide some local cushioning at the same time. This will allow the pelvis especially but also the shoulders to “come to rest” at a higher level which means the foam under your lumbar curve will also be less compressed and you will have a little less support (and pressure) in the areas you are not used to being quite so “supported”. This would likely be the “best” fix if your own personal preferences were unable to accommodate the change in pressure distribution of your mattress.
If the ILD’s of the upper layers were either higher or the upper layers were thinner … then this would also likely change the pressure distribution away from the lumbar curves and torso and onto the shoulders and pelvis as well. As long as the pressure on your shoulders and pelvis is below someone’s personal threshhold … then for that person the mattress is pressure relieving.
Part of the reason too that this can happen over the course of a night or several nights is that this increased support may not be felt as uncomfortable over the course of a shorter time frame but become uncomfortable over the course of a night for those who aren’t used to it.
So in essence … Step one is to wait to see if your new “pressure areas” become used to the increased support. I remember when I first slept on latex that I clearly noticed this as well but to me it was not uncomfortable as much as curious. After a few weeks … it was no longer a curiosity but just part of what I liked.
Step two would be to add a topper that had enough softness to cushion local pressure points but help “prevent” the pelvis and shoulders from sinking in quite as far and lowering the weight being supported in these areas. Of course doing this with a wool topper also means that you will also experience the many benefits of wool without it being a part of the mattress itself meaning it can be replaced if necessary without replacing the whole mattress.
I know this is a somewhat “complex” subject and phenomenon to explain as it involves the specs of different materials and why they create a different experience so I hope that this has helped to “demystify” it more than complicate it.
As a followup to the last post and to come at the same topic from a different direction which may be easier to visualize.
Lets say that someone had a “lumbar recess” (the distance that can be measured if you stand straight against a wall with your shoulders and buttocks touching the wall and measure from the wall to the most recessed part of the small of your back) of 3".
If you took a 5" piece of soft low density polyfoam and put it on the floor … you hips and shoulders would “go through” to the floor (bottom out) and your lumbar curve would be “forced” to compress the foam under it to some degree (less than 2"). Because the foam was soft and also didn’t get firmer very fast … the load that was on your lumbar curve would still be very low and most of your weight would still be supported by your pelvis and shoulders mostly resting on the floor.
If you took a 5" piece of soft HR polyfoam or latex … your hips and shoulders would still sink in about the same but because the foam under the lumbar curve and the torso was firmer (it gets firmer faster with compression) … more of your weight would be supported by these areas and you would feel less of the floor on your pelvis and shoulders and more of your weight would be supported under the lumbar and torso.
Of course neither would likely relieve pressure enough on the hips and shoulders enough with a single 5" layer … but I’m using this to illustrate the reason that the lumbar feels either more “pressure” or “support” (depending on whether this is perceived positively or negatively) with higher quality materials.
This is also why the deeper layers control alignment more than comfort layers because they “stop” the hips at a similar level if the comfort layers are not so thick or firm that the pressure from hips and shoulders don’t “go through” to the deeper layers enough (meaning they are too thick).
Hope this helps to “visualize” this a little more.
As a followup to the last post and to come at the same topic from a different direction which may be easier to visualize.
Lets say that someone had a “lumbar recess” (the distance that can be measured if you stand straight against a wall with your shoulders and buttocks touching the wall and measure from the wall to the most recessed part of the small of your back) of 3".
If you took a 5" piece of soft low density polyfoam and put it on the floor … you hips and shoulders would “go through” to the floor (bottom out) and your lumbar curve would be “forced” to compress the foam under it to some degree (less than 2"). Because the foam was soft and also didn’t get firmer very fast … the load that was on your lumbar curve would still be very low and most of your weight would still be supported by your pelvis and shoulders mostly resting on the floor.
If you took a 5" piece of soft HR polyfoam or latex … your hips and shoulders would still sink in about the same but because the foam under the lumbar curve and the torso was firmer (it gets firmer faster with compression) … more of your weight would be supported by these areas and you would feel less of the floor on your pelvis and shoulders and more of your weight would be supported under the lumbar and torso.
Of course neither would likely relieve pressure enough on the hips and shoulders enough with a single 5" layer … but I’m using this to illustrate the reason that the lumbar feels either more “pressure” or “support” (depending on whether this is perceived positively or negatively) with higher quality materials.
This is also why the deeper layers control alignment more than comfort layers because they “stop” the hips at a similar level if the comfort layers are not so thick or firm that the pressure from hips and shoulders don’t “go through” to the deeper layers enough (meaning they are too thick).
Hope this helps to “visualize” this a little more.
Phoenix[/quote]
Phoenix – yes, this makes sense. In some ways, I almost had the sensation of my lower lumbar “holding up” the rest of my body. When I applied the memory foam topper, this sensation did indeed change from feeling like pushing/discomfort to “support.” The downside though is I feel like the heavier parts of my torso are sagging down too far with this added layer. Plus, all the other downsides of memory foam are brought into the mix. A firmer latex ILD or thinner comfort layer could solve one problem, but then cause another as I do enjoy soft sleeping surfaces.
Hopefully I will just get used to this after an adjustment period.
Exactly. This is because more of this area of the body is experiencing more “pressure” than it is used to. In other words … the support under the lumbar curve is too much because “lighter support” is what is usually needed here. The question is always though “how light or how firm” rather than just one end of the spectrum or another. when you add the memory foam … then it will actually reduce the pressure you are feeling here because it will “flow” away from the pressure more meaning that other heavier areas of the body will take up the pressure that it is “losing”.
Even the work “lumbar support” that is so commonly talked about has two different meanings. One is about the lower lumbar and where it joins the pelvis and the ability of the mattress to hold up this heavier area and prevent the pelvis from “tilting” as much and causing lower back issues with hyperextension of the spine. This is controlled by the deeper layers. The other is all about how much the foam on top compresses under the lumbar curve and fills in the gap and holds up this area of the spine (which is naturally curved and doesn’t need the same degree of support as the pelvis). This is controlled mostly by the comfort layers. This is very connected to the “reverse zoning” thread and the reasons why some forms of zoning can create “too much” lumbar support and create issues … especially if the hips and pelvis are allowed to sink in even further than a normal single zoned layer and transferring too much pressure to the lumbar curve.
If you don’t get used to it or even come to enjoy it after the “transition period” that is connected to any new mattress then a layer on top of something like wool or even a thin firmer foam layer will reduce the amount your pelvis and shoulders sink in while still cushioning them and “lowering” the pressure under the lumbar. Adding more soft material that “compresses” like soft latex or memory foam of course takes the risk of creating misalignment because it may allow your hips to sink in too far relative to other parts of your body but a firmer foam or wool will not have the same risk because it will help to reduce the sinking in rather than increase it. Even something like a fiberbed that compresses easily can increase the surface area of the hips and shoulders enough to reduce the amount they sink in and lower the pressure on the lumbar curve. In other words … either very soft and compressible fiber that both provides cushioning to smaller areas (like the hips) and also reduces how far they sink in or a firmer layer that changes the overall weight distribution away from the lumbar curve can help. The only thing to avoid with your 4" of relatively softer foam on top (for your weight) would be an additional layer of soft foam that compresses and adds to the depth your heavier areas sink in.
I did sleep very well last night and hope I adjust, but really do wonder if I am putting a tad too much stress on the lower back with the sinkage.
Given the benefit of hindsight, as well as the information you have provided, I am beginning to wonder if I would have been better off getting the Pamper with the two inch 14 ILD topper. Firm base of support for my size, but with the added plushness of the topper. I am pretty sure this would work fine for back sleeping, but wonder how it would work out for the occasional side sleeping.
What do you think? Something I am going to have to consider if I end up doing a comfort exchange.
The pamper has a 40 ILD base and an inch of 19 ILD talalay on top. With your weight … I would strongly suspect that 14 ILD talalay in a 2" layer may be so soft that you would still feel the firmness of the core when you were on your side. You could go with a 3" layer of course (although the PLB toppers are quite expensive) and this may give you enough to isolate you from the firmer core and because it was softer than what you have would likely distribute less pressure onto your lumbar curve.
I think though that reducing the thickness to a 3" comfort layer (the existing 1" in the pamper plus a 2" topper) for a mainly back with some side sleeping would help more rather than softening the foam if it becomes necessary but this would probably need a firmer topper than 14 to prevent you from going through so easily to the firmer base layers. The thinner upper layers would be less compressed and have less “pushback” (the 40 ILD would “stop” the sinking in even sooner) and a firmer topper would help to isolate you more from the firmness of the core (you wouldn’t go “through” it so easily). I would think a minimum of 19 and possibly a little firmer yet would likely work better.
The other option of course would be the Nature which is the same as the Nutrition except it has an inch less of the 28 ILD which would be a logical pick for someone of your weight and height who was a combination back/side sleeper with more on their back than side. It would be a little less “plush” but the layering may be more suitable. Did you happen to test this one? I would probably consider either this or a thicker wool topper on what you have if you want a plusher feel.
This is quite unlikely with the layering of the Nutrition and the fact that it uses single zone layers. It’s far more likely that it’s more a matter of getting used to it and/or a matter of preference that you hopefully come to like (with of course the possibility that you won’t) rather than putting “too much” stress on your back in terms of being in any way harmful.
Unfortunately, it does not seem like this is getting any better. I am getting used to the push feeling while awake, but not while asleep, if that makes sense. I am finding that I am mainly sleeping on my side, probably to avoid the push sensation. My lower back remains sores. It is looking more and more like this one will have to go back… unless there is some reason to believe it might get better?
If I have to exchange, I am not sure if I’ll go for another latex model that has few comfort layers (which I believe as you explained is the cause of the push sensation, since my heavier body parts sink right through the soft top layers with the material then pushing on the back), as this would likely turn into a final sale. Going for a conventional mattress may be the safer pick.
Question: I understand there is a truism that you can make a too hard latex bed softer with more layers, but not the reverse. Why is that? Don’t you personally have soft layers at the bottom of your mattress?
An adjustment period of 4-6 weeks or so with no improvement along the way in any discomfort would give a good indication that the mattress wasn’t working for you. While some people will “take to” a new mattress right away, it is not unusual at all for this to take longer. I would use any changes or improvements along the way as an indication of the “direction” any adjusting is going … if it’s changing at all … and how long it may be worthwhile waiting before you pull the trigger on an exchange.
If you do decide to go in this direction … then knowing the quality of any polyfoam in the mattress would be very important to help prevent a mattress that works well from “going downhill” in a different direction and affecting you down the road for different reasons. Other combinations such as latex over innersprings or memory foam may also be worth exploring as some people who don’t like an all latex mattress do very well with some of it in the mix (or other high quality materials) … and if this works for you then you know that you have a quality mattress that won’t soften or degrade prematurely.
This is true with any material not just latex. This is because when you put firmer materials on top of softer materials in an effort to improve alignment … the firmer materials will still follow the contours of the softer materials or any sags or soft spots underneath and while there may be a small improvement … it won’t correct the fundamental problem which is a support system which is too soft to hold up the heavier parts and keep them in alignment. The firmer layers on top will still “bend” into the layers below. On the other hand … if a mattress is too firm … then you are building on a good support system and you can add softer layers to isolate you from the the firmness of the support and improve pressure relief.
I do have softer layers than “normal” at the bottom of my mattress (it’s two sided and has a comfort layer at the bottom as well) as well as in the middle (it’s only 28 ILD). If this for some reason was too soft … I wouldn’t be able to fix it without tearing the mattress apart and adding firmer layers on top would not improve support to any significant degree. This construction would be “risky” for most people.
While you can make “fine tuning” adjustments by adding firmer layers on top (such as wool for example or a thin layer of firmer foam) … they will only have a smaller effect on support and alignment. What is more likely to help in some cases (depending on the mattress construction) is something that can firm up the deeper layers (like a tension adjustable base) underneath the part that is sinking down too far to firm up the support in the “problem” area and hold up the heavier pelvis from below. Firmer layers on top of materials that are too soft are not the solution in cases like this unless the improvement needed is smaller. In other words … support issues primarily involve the lower layers (unless the top layers are so thick that part of them is acting as transition or support layers) and adding firmer layers on top usually ends up putting the softer top foam down deeper into the mattress which can affect support even more.