Just bought my first foam mattress. Have numbing arms at night. Help.

Hi Mysterium,

This mattress is made by Zinus which owns the trademark for “real mattress in a box”. They are a Chinese manufacturer that uses mostly low / mid quality materials although they are CertiPur certified. They are most commonly sold under many brand names in big box stores and elsewhere. Whenever you see “green tea” you can assume the manufacturer is Zinus.

I would also read post #6 here about mattresses imported from Asia or China and which may have been compressed for long periods of time in either shipping or storage before being purchased and a forum search on Zinus (you can just click this) will bring up more information and feedback about some of their brands and mattresses. Being sourced in China make this somewhat of a risky purchase IMO.

[quote]I am a side sleeper - I found myself waking with my arm going numb throughout the night. The numbness would be on the side I am sleeping on.

What causes this? [/quote]

Technically, limbs “going numb” are usually caused by a lack of pressure point relief.

Each person has a range of tolerance for both pressure relief and alignment (the two main functions of a mattress) and there are many methods that are part of mattress theory and design to deal with both of these and how they interact so that both are within the range of what someone needs and prefers in their mattress. While pressure is never relieved down to “zero” … as long as it is within the tolerance of the individual both in terms of their perception and comfort and in terms of any restriction of the capillaries and blood flow in the areas of the “bony prominences” then different types of mattress construction and materials can achieve both the pressure relief and alignment that someone needs yes. There’s lots more information about this in the “mattresses” section of the site and in the more detailed information at the end of this post that describes how and why different materials and types of construction can be used to achieve both.

While this can involve a combination if technical knowledge and intuition in many cases … the fact that almost everyone has found a good combination of both … at least at some point in their lives (maybe not at the moment while they are looking for a new mattress) … says more than anything else that both pressure relief and alignment as well as the many other personal preferences that are unique to each individual but also need to be included as part of the mattress design are possible for the vast majority of people that don’t have health or other issues that puts them outside of needs and preferences range of the majority of the population.

There is little consensus information about pressure relief … even in a hospital setting that deals with treatment of pressure ulcers and there is a great deal of information that needs further research. Technically, to qualify as a “pressure reducing support surface”, a mattress needs to reduce pressure to below 32 mmHg (also called a Torr) on “most bony prominences most of the time”. Bony prominences are the bones and joints in each sleeping position that protrude and have less tissue between them and the surface. To qualify as a “pressure relieving support surface” pressure needs to be reduced to below 32 mmHg (Torr) on “all bony prominences all of the time”. This is also not quite accurate as fixed numbers like this are not considered to be completely accurate or valid anymore as research continues.

So if you can create just enough “sinking in” to distribute pressure points over a wide enough surface area around the body prominences using comfort layers (and the upper surface of the middle layers if necessary) of various types and which will deal with the support needs of the recessed areas of the lumbar, then the only remaining issues are issues of alignment. This is controlled by the middle and deeper layers of the mattress and they need to prevent or “stop” any further sinking down of the heavier areas than are necessary (hips and pelvis primarily) to prevent them from sinking in further than necessary for pressure relief which could put the spine out of it’s natural range of good alignment.

In other words … the upper layers are about “allowing” enough sinking in to create the mattress cradle which is a larger area of surface contact with the mattress to relieve pressure and support the recessed areas of the spine. The deeper layers are about controlling any further compression than necessary for pressure relief to “hold up” the heavier parts of the body and keep the spine in its range of natural alignment. The amount of sinking allowed by lower layers has less effect on pressure relief in other words (in most types of mattress construction) but controls alignment. This is why when people change the firmness of upper layers to solve support issues or the lower layers to solve pressure relief issues they will often create new issues and may not solve the issue they are trying to “fix”.

Each sleeping position (and the many combinations and variations of each) along with the many different variations of body shape and weight and the natural variations in the range of pressure relief and alignment tolerances for different people (based on their individual physiology, health, sensitivity, flexibility, and other differences) leads to different types of layering working better or worse for different people.

If you can return the mattress (which I would recommend) I would then tell you to start over and “rethink” your mattress buying process. The first place to start your research is the mattress shopping tutorial here which has all the basic information, steps, and guidelines that can help you make the best possible choice … and know how and why to avoid the worst ones. The first step would be to decide on your budget range and decide on the types of materials and the types of mattresses you are interested in trying (or buying).

If you’re unwilling or unable to do that, your pressure point issues may get better as time goes on and the mattress softens (you didn’t mention how long you’ve had the product). You could also add a topper for extra plushness. If the issue is alignment, that won’t get better over time. You didn’t mention what type of foundation you’re using, so you’d want to be sure that it isn’t sagging. You could also modify the manner in which you sleep on your side, using a body pillow upon which you could rest your free hand. You can also make sure you pillow is thick enough to support your head in good alignment, and you can also place a pillow behind you and slightly lean against that to take a bit of stress off of your shoulder joint.