Hi Phoenix,
Will the ILD of a NR latex core soften enough that it’s ILD rating changes?
Is there a break-in period on a new mattress where the latex softens in the first few weeks, or does the softening process take years?
Would a 3 layer (3" cores) mattress of medium, firm and extra firm all change to a softer feel or just the top layer?
Thanks!
Hi Gail J.
Any change in firmness (even the smallest) would change the ILD of a material to some degree but ILD ratings aren’t exact and are inside a range anyway so it would normally still be inside the same ILD range. Most people wouldn’t notice ILD differences that are about 3 ILD or less anyway.
There will be an initial break in period with any new mattress or foam material (including latex) over the course of the first few weeks after which any changes would be much more gradual over a longer period of time (see post #3 here).
The regular deflection/compression of a foam material is what softens or breaks down foam over time and softer upper layers of a mattress will deflect and compress more deeply and more often than firmer deeper layers so foam softening will happen more with softer layers and/or layers that are closer to the sleeping surface than with firmer layers or layers that are deeper in the mattress. Latex in general though is the most durable of all the foam materials so foam softening and break down will generally happen less and more slowly than with other types of foam.
Phoenix
Thank you Phoenix. Your reply was very helpful and the link was too.
I notice that reading in bed on a latex mattress is difficult for comfort, as I sink in. I need to sit on a pillow, so I don’t sink in too much.
Will sitting on the latex mattress in the same spot to read, cause the mattress to have a big depression over time? Would you recommend against doing this?
Thanks again!
Hi Gail J,
This is a common with latex because it’s very “point elastic” (meaning it can contour and compress in a specific area with less affect on the surrounding area) so you can sink in more deeply with the more concentrated weight of sitting vs the more evenly distributed weight of lying down and mattresses are designed to evenly support your body weight when you are lying down.
It would probably help to use an adjustable bed underneath your mattress which will help to support your weight and back more evenly along the length of your body when you are sitting up so you don’t sink in as much in one specific area.
The depth, frequency, and length of time that a foam material deflects or compresses is what softens the material over time so sitting on a mattress over longer periods of time can result in more foam softening under the area where your weight is most concentrated than lying on a mattress yes … even with materials that are more durable such as latex.
There are too many variables involved to be able to predict “how much” or “how quickly” that area of the mattress will soften relative to the other parts of the sleeping surface or whether or when any foam softening in that part of the mattress will take you outside of the comfort/support range that would be suitable for you to sleep on outside of saying that it would soften faster than it would if you weren’t sitting on it on a regular basis.
I don’t recommend either for or against it (we have an adjustable bed that we use for reading although not on a regular basis) … my goal is to point out the pros and cons of both sides so you can make a “best judgement” choice about whether any durability trade-off is worth it to you.
Phoenix
Thank you again Phoenix,
It’s so nice to have a trusted and informed voice on this,
It all makes sense,
Would it be fair to say that say, after 10 years of use, a latex mattress would have softened enough that the previous “medium” ILD of a top core layer, might register as a “soft” ILD?
Or is it more that the latex will be compressed and not be very supple and hence just feel less supportive or comfortable?
Thanks!
Hi Gail J.
Unfortunately your questions are too subjective to be able to answer with any specificity,
There are no “standard” definitions or consensus of opinions for firmness ratings and different manufacturers can rate their mattresses very differently than others so a mattress that one manufacturer rates as being a specific firmness could be rated very differently by another manufacturer. Different people can also have very different perceptions of firmness and softness compared to others as well and a mattress that feels firm for one person can feel like “medium” for someone else or even “soft” for someone else (or vice versa) depending on their body type, sleeping style, physiology, their frame of reference based on what they are used to, and their individual sensitivity and perceptions. There are also different types of firmness and softness that different people may be sensitive to that can affect how they “rate” a mattress as well (see post #15 here) so different people can also have very different opinions on how the same mattress compares in terms of firmness as well and some people may rate a mattress as being firmer or softer than someone else. This is all relative and very subjective and is as much an art as a science.
“Support” is often misunderstood and many people believe incorrectly that “firmer is better” or “more supportive” when the real goal is to keep the spine in good alignment and this requires the type of contouring support that allows some parts of the body to sink in more and some parts of the body to sink in less and this will vary on an individual basis. There is more about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may also be helpful in clarifying the difference between “support/alignment” and “comfort/pressure relief” and “feel” and how they interact together.
If an individual top layer softens or loses about 10% of it’s original ILD and the original ILD was say 24 then it would lose 2.4 ILD so it’s unlikely that most people would notice this. If it loses 20% of its original ILD then it would lose 4.8 ILD in the area that had softened the most and some people may notice this and some may not.
The only way to know how your mattress will feel for you after 10 years of use or whether you will still be sleeping well on it then will be based on your own personal experience at that time. One of the additional advantages of a component mattress with individual layers and a zip cover though is that if the softer comfort layers soften or break down before the deeper layers in a mattress (which is most likely) and if the softening is affecting how well you sleep or if your needs and preferences change down the road you can replace individual layers instead of having to replace the complete mattress.
Phoenix
Thanks yet again.
I appreciate your patience!
And all the information!
It makes sense and I will be reading the links within your post.
I appreciate the specificity on the possible ILD numbers over time.
Gail