Your mattress is one of the most important things you will purchase. Most of us have limited time to spend in bed, and it is important that we get the best quality rest while when we do. The right mattress should feel supportive and comfortable, as if your entire body could melt into it.
Most mattresses come with a firmness rating scored on a scale from 1 – 10, with 10 being the firmest. Additionally, most mattress retailers equate firmness to support and claim that firmer mattresses are necessarily more supportive. Unfortunately, the idea that the firmness rating is all that matters is just a lazy way of selling mattresses, and often lead to much agony on the part of customers who just don’t know any better.
Firmness VS Support
The firmness and support of a mattress are related, but very different properties of a mattress.
The support of a mattress is its ability to keep your spine in its natural alignment without active involvement of your muscles (which do the job when you’re awake). A mattress that lacks support usually leads to tight and sore muscles in the morning, a feeling of fatigue even after long hours of sleep, and can even be the cause of back pain. Support is a primarily a function of the middle and lower layers of a mattress – they must be carefully designed to respond to the different weights of your body parts and keep each one in it’s natural alignment.
The firmness of a mattress refers to how much the topmost layers of the mattress accommodates and contours to your body. It is what we identify as comfort when we first lie down and is more of a personal preference, but will also affect how underlying support is transferred to your body. Mattresses that are too firm may result in shoulder and hip pain, while mattresses that are too soft may feel downright uncomfortable for people who prefer a little more responsiveness.
A supportive mattress can also be soft (think of plush hotel beds), while a firm mattress can also be extremely unsupportive and put your spine in really unnatural alignments (think of a bare wooden board).
Do not go for a ultra-firm mattress just because you want a supportive one!
Ability to keep spine neutral and muscles relaxed
Function of lower and middle layers
Prevent muscle aches and tightness
Non-negotiable: all mattresses must be supportive
“Feel” of a mattress
Function of uppermost layers
Prevent joint aches and soreness
A matter of personal preference and sleeping habits
Can affect how underlying support is transferred
Which mattresses have good support?
With the exception of innerspring mattresses, most modern mattresses are excellent at providing support. An innerspring mattress is a big interconnected mesh of springs connected to a single metal frame – like a metal hammock. Heavier parts of your body like your hip tends to sink more into the mattress, and this becomes a problem with innerspring mattresses because the weight also pulls down on the areas of the mattress surrounding that body part, which takes away support from these surrounding body parts. This is why innerspring mattresses can lead to lower back tightness and soreness in the morning.
Modern mattresses like the box spring (pocket coil), and various foam mattresses greatly alleviate this problem because different parts of the mattress can compress to different extents without greatly affecting the areas around it, allowing it to support your spine in it’s natural position.
What is a good mattress firmness?
Mattress firmness impacts how a mattress feels to your body and is mostly a function of personal preference. While some may prefer a plush bed of feathers with a lot of give, others may prefer firmer mattresses with minimal give. You should always try mattresses out and choose one that feels comfortable. Before we go over some factors to consider, here are the different firmness ratings and what they mean.
Soft
Firmness Rating: 1-3
Soft mattresses have almost no resistance from the topmost layers. It is important to emphasize that we are referring to the top layers which are only about 1-3 inches thick so the mattress can remain very supportive and you can even feel these support layers if the top layer is soft enough. These mattresses feel almost like a quilt – luxurious and plush.
Common examples of soft mattresses are pillow-top mattresses. One problem with pillow-top mattresses, however, is that the lower density pillow-top layer tends to lose its fluffiness before the support layers have worn down, and you end up throwing away a perfectly supportive mattress worth thousands that just doesn’t have the plush feel you crave anymore. A wiser alternative is to purchase a firm, supportive bed, and add on a pillow-top mattress topper on top. These are very much cheaper to purchase, and can be replaced easily when they lose their softness.
Medium
Firmness Rating: 4-7
Most people tend to prefer mattresses of medium firmness. They can be further categorized into medium-soft (4-5) and medium-firm (6-7) mattresses. These are commonly made of a variety of foams such as memory foam, latex, etc, which can be manufactured to different firmness easily by altering their compositions. Medium mattresses accommodate the contours of your body while still providing enough resistance that you do not feel the firmer support layers beneath. This can be great for sleepers who experience too much pressure on some joints from their sleeping position. Most luxury hotel beds are in this category.
Firm
Rating: 8-10
Most people would find mattresses in this range uncomfortable. They are also less commonly made and thus more expensive. However, there is a niche for them for heavyweight sleepers, stomach sleepers etc.
Sleeping position
Your sleeping position is an important factor in determining what mattress firmness feels comfortable to you because it determines which points are supporting most of your weight. For example, stomach sleepers will exert more pressure on their hips than back sleepers.
Side sleepers
Side sleepers generally do better with a soft to medium-soft mattress (or a memory foam one, explained below). With bony, protrusive shoulders and hips, and soft, fleshy abdominals, our body contours are most exaggerated on the sides. A firm mattress pushes your shoulder and hips out of alignment in order to support the abdominal area, which leads to shoulder soreness and muscle imbalances in the hip area. Softer mattresses accommodate these joints and allow your arm to be tucked under without numbness nor tingling.
Stomach sleepers
Stomach sleepers should opt for a firm mattress. A firm mattress prevents your hips and pelvis from sinking lower than your shoulders and creating an unnatural arch in the spine, which can lead to back tightness otherwise. Box spring and extra-firm latex mattresses will be suitable.
Back sleepers
Sleeping on your back is recommended by most sleep experts, because it distributes your weight across the full length of the body’s largest surface. Back sleepers will find most mattress firmness suitable, but population preferences generally fall within the medium range. If you want to bump comfort levels up a notch, you can give memory foam mattresses a go. Memory foam does not conform to traditional firmness standards abut selectively gives to provide optimal weight distribution and support.
Body weight
Body weight may pose more of a problem when finding a comfortable mattress for overweight individuals. Softer mattresses, especially those composed entirely of softer foam, may sink too low if you are overweight, making it hard to get out of bed and even compromise the support it is designed to provide. If you are heavyset but still prefer a soft mattress, we recommend getting a firm box spring one topped of with a softer mattress topper. Hybrid mattresses composed of several layers of foams of different firmness will work as well.
Memory foam does not follow traditional firmness ratings
While memory foam mattresses are also commonly assigned a firmness rating, these scores are less meaningful to memory foam because it is viscoelastic. Viscoelasticity is a technical description of memory foam’s ability to have the weight distribution properties of a liquid and the elasticity of a solid.
The responsiveness (“firmness”) of memory foam decreases in response to heat. Heavier points of your body such as the hips and shoulder heat up the memory foam mattress more, selectively decreasing the responsiveness of these areas and allowing these parts to sink in more without experiencing significantly more pressure. The memory foam remains firm under less protrusive body parts like your lower back. The result is that memory foam molds to your body and distributes supportive pressure evenly across the entire surface, in contrast with other mattress materials that tend to put more pressure on the shoulders and hips. Hybrid mattresses with a memory foam layer on top will transfer support from the underlying layers in a more optimal manner and accommodate all sleeping positions. This is why many people find that using a memory foam mattress topper on top of a overly firm bed changes the experience entirely.

Memory foam can accommodate the different weight profiles of various sleeping positions.
Memory foam has to allow your body to sink into it to work properly, and hence may feel “soft”. However, the softness from its viscoelasticity will feel very different from that of pillow-top mattresses – almost like floating in zero-gravity.
Though memory foam bedding is revolutionizing our sleep experience, heat retention is a major drawback especially for people who sleep hot or in tropical climates. We at SleepWiz have made a major breakthrough in overcoming this limitation with our ErgoLush™ Gel-infused Memory Foam Mattress Topper, which combines open-cell structure, air vents, and an innovative conductive gel infusion all aid to cool the mattress down.