Choosing a mattress
The mattress for the comfortable user
The mattress is a personal thing. It's like shoes, but far more complicated to find a good match. Just as shoe size is strictly related to the size of the sole, the mattress is strictly related to the height, weight (distribution), constitution and health issues of whomever sleeps on it.
The purpose of a mattress is to provide support and comfort to the people who sleep on it. The support comes from bottom layer of the mattress, and the comfort comes from the top layer.
The relevant factors in deciding what mattress to choose are: your body type and particularities, your health particularities, your budget, the desired quality of the mattress. The mattress type (springs, latex, memory foam, or polyurethane foam) isn't such a factor.
It can not be stated more firmly (pun intended) that the saying "a firm mattress is good for the back" is an evil advice which should only be given to enemies. If you are slim then choose a soft mattress, if your weight is average then choose a medium firmness mattress, if you are overweight then choose a firm mattress, but see below why it's more complicated.
To choose a mattress, go to the store, lie in your preferred positions on as many mattresses as you like, stay there for as much time as you can, and buy the one that feels best for you and that you can afford to pay without living your life to pay for it. When testing, follow the advice below.
A bed isn't tested by sitting on its edge, not for sleeping, anyway. When sitting, the entire weight of the body presses on your bottom (which then presses on the mattress), whereas during sleep only the weight of the bottom presses on the mattress (in the bottom area), which means that this kind of testing, sitting, makes the mattress feel much softer. Also, the edges of a mattress are either its softest or firmest spots.
Is lying for a few minutes on a mattress a guarantee that you will make a good choice? No, but not lying on a mattress at all is more likely to lead to choosing a wrong mattress.
When lying on your back, your bottom and the middle of your back have to push in the mattress, and your head has to push in the pillow, all without causing pressure / pain to your bottom, lower back, middle of your back and neck; "middle of back" is about at nipple level, where the backbone is curved the most outward.
When you lie on a mattress that's too firm for you, your bottom sinks very little in the mattress, and your lower back stays too high to touch the mattress. This creates a gravitational pressure in your lower back, pressure which will cause pain after years or decades of sleeping like this. If you can't replace the mattress, a way to reduce this effect is to put some pillows under your calves or knees.
When you lie on a mattress that's too soft for you, your bottom sinks in mattress until your lower back starts pushing in the mattress. Therefore, your lower back has to support more pressure, and this will cause pain after years or decades of sleeping like this.
When lying on your side, your hip and shoulder have to push in the mattress, and your head has to lie on the pillow, all without causing pressure / pain to your hip, lower back, side chest and neck; "side chest" is about at nipple level.
You must use a pillow which fits both your body and the mattress that you are lying on. Try multiple pillows with the same mattress.
If while you relax on a mattress you start to feel sleepy after a few minutes, the mattress is a good candidate for the final decision.
Do this several times, weeks or even months apart, so that your body and mind adapt to all the mattresses.
For adults, a mattress should:
According to this survey, the general opinion is that the highest owner satisfaction is for memory foam (81%) and latex (80%) mattresses, while the lowest is for spring (64%) mattresses.
There are mattresses with several zones of different levels of firmness. This is very good for side sleepers because the mattress can be firmer in middle in order to hold most of the body's weight (= the bottom), but softer in the shoulder area in order to allow the shoulder to sink in the mattress, so that the neck remains a straight line. However, these zones are fixed in size and position, so they might not fit your body's height, structure and sleeping positions. The more zones there are, the easier it's for you to lay on the wrong zones (which are the opposite of what you need). If the cover is removable, it's easier to see where each zone goes.
Some latex mattresses / cores have a bump in the middle, where the bottom is supposed to stay. This is meant to offer more support to the bottom. If possible, avoid such mattresses / cores because, unless your bottom lays perfectly on the bump, the bump will put undue pressure on your thighs (if you're short) or lower back (if you're tall), pushing into them and interfering with your blood circulation, especially for side sleepers.
When you consider the cost of a mattress (and of any accessories), think at the price that you are willing to pay each month for a mattress which will literally have your back.
You will probably change your mattress every 5 to 10 years, maybe with an average of 7. There are 7 * 12 = 84 months in that period, so multiply this with the amount of money that you are willing to pay each month. This should be the maximum price of your mattress.
See this for a way to determine if you can afford things in general.
Hygiene studies for different types of mattresses are conflicting, so don't choose your mattress type based on hygiene claims for that type.
For example, this study has found that foam mattresses contain more dust mites than spring mattresses. However, the authors recognize that another study has reached the opposite conclusion.
A mattress should be as thick as possible. The thicker it is, the more comfortable it can be. However, the minimum thickness depends a lot on the type of bed foundation the mattress is put on, and on the weight of the people who sleep on it.
For a DIY mattress with multiple layers, you can stop whenever you feel comfortable.
The thickness refers to the thickness of the springs and foam, it excludes the thickness of any fiber filling (like those usually found in the cover).
If you have a spring bed foundation (/ box spring), the height of its springs counts toward the mattress thickness.
A foam's density is independent from its firmness. High density foams can be produced to be very soft, and low density foams can be made to be very firm. For example, a 25 kg / m3 polyurethane foam can be firmer than a 65 kg / m3 latex.
For latex, the firmness is mostly proportional with the density. The firmness varies from extra-soft for a density of 65 kg / m3, up to extra-firm for a density of 95 kg / m3. However, for the same density, the firmness varies depending on the manufacturing process, and from manufacturer to manufacturer.
Density directly affects the durability, and therefore the support properties, of foam. A very high density foam (like latex) is much more durable than a very low density foam (like polyurethane). The reason for this is that a higher density foam spreads the weight of the sleeper over more material, so each individual foam cell is compressed / worn less, which means that its life is extended.
Here (see the data sheet) is a test made by a manufacturer of spring bed components. The test has performed a large number of compressions of different types of materials: (their) springs, latex, memory foam, polyurethane foam. After the test, the percentage of height degradation was measured for each material, relative to the original height. After 100'000 compressions the results were (as a degradation percentage): springs - 5%, latex - 23%, memory foam - 16%, polyurethane foam - 49%. The densities of the foams were not specified, which means that we can't know why the latex and memory foam have behaved so differently; for the same density (65...85 kg/m3) they should behave similarly. It's no surprise that the steel springs had the least degradation, and that the polyurethane foam had the most degradation (since it always has a much lower density than latex and memory foam).
Latex and memory foam density should be at least 65 kg / m3.
IFD (Indentation Force Deflection) is the number of kilograms of force required to indent a foam sample by a specified percentage of its original thickness.
It's common to measure IFD using a 20 cm (= 8 in) metal disc that presses a 10 cm (= 4 in) thick sample of foam until a 2.5 cm (= 1 inch) high indentation is created. The force in kilograms required to obtain this indentation is the IFD.
Lower IFD numbers indicate a softer foam, while higher values indicate a firmer foam.
Foam provides a gradually increasing resistance to the compression of the weight that sits on it, as the weight pushes through more and more foam. This means that the foam becomes firmer and firmer as it's being more and more compressed. This means that the IFD increases as the indentation percentage increases.
IFD is also known as ILD (Indentation Load Deflection).
Foam firmness is represented by the IFD.
The deep firmness shows the support feel of the foam, and is represented by the IFD measured at 65% tall indentation.
The surface firmness shows the comfort feel of the foam, and is represented by the IFD measured at 25% tall indentation.
The compression modulus is the foam's ability to prevent the body from reaching the bottom of the mattress.
The compression modulus is determined by dividing the IFD required to obtain a 65% tall indentation in the foam, to the IFD required to obtain a 25% tall indentation in the foam.
A common compression modulus for high quality foams is 2.5.
The durability of a foam mattress depends on how well the foam retains its original compression modulus (and firmness). In time, under regular compression, the foam loses these characteristics and no longer provides support to the body, usually around a person's bottom because that's the area which is exposed to the highest weight.
As years pass, while sleeping on the foam, you will start feeling how your bottom sinks in more and more. If you look at the foam in that area, there might be no visible difference, that is, the foam will likely regain its original thickness after you get off it. However, the foam cells gradually lose their ability to sustain weight and, at some point, you sink in right through the top layer of the foam, that is, there is no more gradually increasing compression resistance.
This is why a mattress guarantee that specifies a number of centimeters / inches of indentation is irrelevant for long term wear, considering that it's possible that even though there is no such indentation, the mattress is no longer fit for sleep.
Resilience is the degree of bounciness / springiness of a mattress.
Springs, latex, and non-memory foams have resilience, that is, once the body moves on them they instantly change their shape. Latex has a very high resilience, while memory foam has a very low one.
The slowness with which memory foam reacts when it's exposed to heat, both when deforming and when regaining its factory cast shape, leads to a lack of bounciness, and this provides motion stabilization to the body.
The lack of bounciness of memory foam affects sex because thrusting has no immediate feedback / bounciness.
Heat retention is body heat which is retained by a mattress when you lie on it; because this heat is not absorbed by the mattress, it creates a discomfort by overheating the person who lies on it.
Foam mattresses are generally affected by this problem, with memory foam mattresses being affected the most. Heat retention is in fact the biggest disadvantage of memory foam mattresses, toppers and pillows.
Heat retention can be reduced a bit during the manufacturing process by reducing the memory effect, or by drilling narrow, vertical tubes through the mattress / pillow.
Heat retention can be reduced by sleeping on a mattress cover made with bamboo fibers.
If you feel that your mattress retains heat, you could try to sleep with very thin pajamas or none at all, and cover yourself with only a bedsheet (not a blanket or duvet).
Spring mattresses are theoretically immune to this issue since they are mostly empty around the springs. However, modern spring mattresses have a foam layer at the top, layer which retains heat.
Why does heat retention happen? Why do some mattresses feel cool while others feel hot?
You may hear it has to do with ventilation / air circulation, but the actual reason is thermal comfort, specifically, heat balance (= body generated versus lost through materials).
Thermal comfort depends on how much heat your body is generating and how much heat it loses through the various materials that cover you. It also depends on what the temperature is beyond the materials that cover you, and on how fast the room you are in loses heat to the outside (which, again, depends on the temperatures inside and outside, and on the thermal insulation of the home).
Specifically, thermal comfort depends on the thermal conductivity of the materials, that is, on the thermally insulating properties of the materials that cover you (where the mattress is covering your back).
Foam is a good thermal insulator because it traps air inside, air that can't easily circulate to escape to the outside (or come in contact with the mattress cover). A good thermal insulator has a low thermal conductivity, which means that it transmits little heat from you to it and then to the outside.
You can read more about thermal comfort here.
A mattress made with quality springs which has no foam in it, has a very high lifetime. This reduces the long-term cost and waste of the mattress. Such a mattress doesn't have the bad smell that foam mattresses are known for.
Spring mattresses contain springs made of steel (some are made of wood). The mechanical characteristics of steel are not found on mattress labels, so you can't make an informed decision.
Spring and foam mattresses have strengths and weaknesses. Arguments that make foam mattresses look generally superior to spring mattresses are made in order to profit from your lack of knowledge.
The only comfort-related disadvantage that most spring mattresses have is that they contain low density foam (like polyurethane) and low density textile (like cotton), layer that breaks much faster than the springs below. Steel is the last thing to break since it's much more durable than any foam or textile material.
If you want a durable spring mattress, look for one which has no foam over / under the springs; the springs have to be covered only with felt (which is a very high density textile). If you can't find a mattress like this, look for a spring bed foundation (/ box spring). On top of this, put a topper made either with springs (like this) or latex. This will allow you to change the topper when it no longer provides you comfort, without throwing away the bulk of the mattress (the springs below the topper).
A disadvantage not related to the comfort of spring mattresses is that generally they are not vacuum packed (in small packages), like foam mattresses are, although some are. This can be a problem in tight spaces.
Another disadvantage not related to the comfort of spring mattresses is that they are a bit noisier than foam mattresses. This is due to the noise made by steel when it's (de)compressed.
Modern spring mattresses are made with pocket springs where each spring is individually wrapped in a textile pocket. Since there is no steel connecting the individual springs, such a mattress is very good at keeping motion in the place where it happens, instead of propagating it on the other side of the mattress, meaning that if you get up during the night, your partner will be less likely to be awoken by the movement of the mattress. They are also more quiet than the mattresses made with connected springs.
Latex is a rubber with excellent elastic properties, which can be used for both the support and comfort layers.
The benefits of latex are: it's supportive yet soft, has excellent bounciness (which people like during sex), it's lifetime is much longer than polyurethane's, and doesn't have the heat retention of memory foam (so it feels cooler during sleep).
Latex quality varies significantly. Something which is called "100% latex" could contain less than a third natural latex, while the rest is synthetic latex (to reduce the price); you can't see the difference just by looking at latex because all the components are blended. Considering that a slab that's made from 100% natural organic latex costs, for example, 4 times more than a cheap latex slab, you can see why most people shouldn't reject latex which is not all natural.
The people who sell mattresses which contain synthetic latex claim that the durability of such mattresses is greater than the durability of the mattresses which are 100% natural latex, claiming that 100% natural latex breaks down faster (due to aging). The people who sell mattresses which are 100% natural latex claim the opposite. It's possible that the opposite results are obtained when trying to keep a low price for the mattresses which are 100% natural latex, which leads to using low quality latex and recipes. The firmness may also be affected by synthetic latex, either up or down.
Beware that just because something is labeled "natural" doesn't mean that it is, especially if it's cheap (to attract buyers).
Latex, natural or synthetic, emits a bad smell, like foams generally do, although not for the same reason: latex smells because it's vulcanized, while polyurethane foam smells because of its chemical composition. Synthetic latex smells for both reasons.
Some manufacturers call their mattresses "latex" even though they have only a thin layer a latex.
Here's what the EuroLatex association says in it's FAQ about latex allergy: "When it comes to mattress cores, ... according to the medical literature, not a single case of allergic reaction has ever been reported as a consequence of sleeping on a natural latex mattress. During the manufacturing process the mattress core is washed thoroughly and then dried and vulcanised. This removes or denatures the proteins responsible for triggering any allergic reaction. Also, the mattress cover and bed sheets protect the skin against direct contact with any allergenic components that might remain. Furthermore people should bear in mind that standard latex foam consists mainly of synthetic latex which does not contain any of the allergenic proteins found in natural latex."
Foam mattresses are normally delivered in vacuumed packages. If a foam mattress sits in a vacuumed package for months, it will give off a bad smell when it's unpacked, even for months.
Memory foam (also called viscoelastic foam) is a foam which slowly reacts to heat in the sense that it slowly deforms to take the shape of a body which sits on it, slowly recasting itself to the shape of the body, and slowly regaining its factory cast shape once the (heat of the) body moves away. As the body moves on the mattress, the memory foam slowly adapts to the new position of the body, not instantly like in non-memory foams.
A memory foam mattresses is not made entirely from memory foam because while it provides good comfort, it lacks supportive properties (= has a low compression modulus). The lack of supportive properties means that memory foam is used only for a thin layer (5...10 cm, 2...4 in) at the top of a mattress, while under it there must be (a thick layer of) springs, latex or non-memory foam.
People who first try a memory foam mattress may find its motion stabilization to be unpleasant. When the memory foam takes the shape of the body, the depression which occurs in the mattress may be too deep (depending on how thick and reactive the memory foam is). Because of this depression formed under the body, moving around and getting up from the mattress requires more effort than on a non-memory foam mattress.
This gives a feeling of being in a caught in a hole (in the ground). However, after a few weeks the body adapts to the new feeling. Still, if you really don't like this feeling, maybe it's your body telling you that it needs to move around during sleep.
Not all memory foams are equal. Some react more intensely than others at the same amount of heat. As the reaction to heat increases, so does the heat retention of the foam, and heat retention is unpleasant in a warm environment. Tempurpedic mattresses are known as having the highest memory effect, but also the highest heat retention. I had a Tempurpedic (memory foam) pillow which made my nape sweat during the summer, but a memory foam pillow from another brand only felt warm (not hot).
Humidity, either from the air or from perspiration, is absorbed by memory foam, which causes it to sag.
Stomach sleepers should avoid memory foam because they would sink in the middle, which would put pressure on the back.
Polyurethane foam has a bad reputation for being toxic compared to 100% natural latex, but its quality varies greatly.
Polyurethane foam is much cheaper than latex and memory foam.
A common density of polyurethane foam is 25...35 kg / m3, so it's much lighter than latex and memory foam.
HR foam (High Resilience foam) is a type of firm polyurethane foam with common densities around 30...55 kg / m3, which means that its durability is higher than that of regular polyurethane foam, but still lower than that of latex and memory foam.
Memory foam is a type of polyurethane foam that contains additional chemicals to increase its viscosity and density.
Fancy-named foams that are not latex, are some type of polyurethane.
Polyurethane versus latex
If a cheap polyurethane mattress works for you, is there any reason to buy a more expensive mattress with springs or latex?
The answer to this question mainly depends on how often you intend to change the polyurethane mattress.
Polyurethane wears much faster than latex. You would think that then you can simply replace such a mattress more often. You could, but then you end up with the same cost per (unit of) time.
All materials gradually lose their ability to sustain weight, which means that the initial compression resistance (IFD) which gradually increases with the depth (from the mattress top toward the bottom) starts to degrade faster and faster. Because the base support layer of mattresses is usually firm, the wear of the comfort and middle support layers will result in an increasingly firmer mattress. The result of this will be pain in the joints, especially for side sleepers whose hips must sink more into the support layers of the mattress.
This happens with all mattresses, regardless of materials, but in the case of a polyurethane mattress you will postpone changing the mattress because you think it has lasted too little time, so you feel obligated to keep it for longer so that you don't waste money, and this will lead to you sleeping for years on a mattress that's unfit for sleeping.
Latex provides both support and softness at the same time because it's firmness is achieved with material density, while polyurethane provides each of these characteristics only at the expense of the other because it's firmness is achieved with material rigidity.
There are manufacturers which have mattresses that have separate foam layers which can be swapped to provide you the firmness that you need.
There are manufacturers which have mattresses that are split in half, one half for each person that sleeps on the mattress. You can unzip the cover of such a mattress and expose its internal foam layers. You can then flip over either half (or even both), so that each person has a half-mattress with a different firmness than the other person. The foam layers are usually glued together, so you can't swap them around.
In order for the two halves to feel as a single mattress rather than two smaller ones, the mattress cover has a foam padding layer which is thick enough to bridge the gap between the two halves.
If you think that this padding is not enough, it's possible to buy a mattress bridge, but these are normally thick and can be felt. A mattress bridge is a filler mat made from a soft material, which is put in and above the gap between two mattresses, under the cover.
A split mattress also gives you the possibility to replace only half of it at a time. For example, you can start by buying a 180 * 200 cm (72 * 80 inches) mattress; later you can replace half of it by buying a 90 * 200 cm (36 * 80 inches) mattress (and taking its cover off).
A split mattress is important for people who sleep together and have significantly different physical constitutions, but also for people who either sell or rent an apartment / house which includes the mattress.
Here is how you can make your own mattress from parts.
Would a DIY mattress cost you less than a ready-made one that's bought from a store? Most likely not, at least not when you first start doing this, but since you can change the parts individually, it's likely to cost you less in the (very) long term. Another advantage is that you can customize it very precisely to your needs, without wasting time going around through the stores to test countless mattresses and still not finding the right one.
You will have to buy several layers of latex, each with a different density (65...95 kg / m3). Remember that for latex the firmness increases with its density.
You should buy the layers one at a time in order to keep the cost as low as possible (because you can stop buying when you reach your target), and to help you when you don't know the density / firmness of the latex.
If you can't find bare latex cores, you could buy normal mattresses that have their entire core made from a slab of latex. This means that while you would pay extra for the cover, you could either keep or remove the cover off the mattress; you should keep it on the mattress.
If the mattress is for 2 people, the bottom layers could be split in half (= made from 2 parts), one for each person. This way, each part could have a different density / firmness, and could be changed separately if it becomes damaged, which in turn would reduce waste and long term costs. This also allows you to stack the halves on top of each other in order to see how it feels to have a much thicker layer with the same density, before you buy the rest of the layers.
If the bottom layers are split in half, the top layer should be full size in order to bridge the split below it; this top layer should be at least 7 cm (3 in) thick.
The thickness of a layer is not important because you can use fewer or more of layers. However, the thicker the layer is, the more costly it will be to replace. If you can find thin latex layers which are 5...10 cm (2...4 in) thick and have different densities, you could fine tune the feel of the mattress by interlacing several of them; also, they are much easier to move than thicker layers.
First buy a layer of latex whose density depends on your weight distribution:
Side sleepers should prefer softer layers. Stomach sleepers should prefer firmer layers.
Once you lay on this layer, if you think that its firmness is:
Once you lay on these two layers, and you switch them around to see which combination is better, if you think that their firmness is:
A mattress should be as thick as possible. For me, a slim person, when lying on a 16 cm (6 in) thick latex slab with a density of 65 kg / m3, I can feel the wood slats of the bed foundation. If there are 2 such slabs on top of each other, the feeling of floating on latex is spectacular.
Not all of the thickness has to be latex. The bottom part of the mattress can be a spring mattress (or a spring bed foundation) that has no foam in its top and bottom layers. The firmness of the springs depends: if the latex is thick (like 15 cm / 6 in) then the springs can be firm, but if the latex is thin then the firmness of the springs depends your body's needs.
For the bottom part of the mattress, a cheaper alternative to latex and springs is polyurethane foam. The durability of polyurethane foam is lower (because of its much smaller density), but since the price is also lower it means that it's a good alternative, especially considering that a prematurely worn layer will be cheap to replace.
If a thick mattress is expensive for you even when using cheap polyurethane, you can decrease the cost by decreasing its thickness, but you have to put the mattress on a bed foundation which supports the mattress with wide wood boards that have holes drilled along their length. Such wood boards provide support in two (horizontal) directions, which means that your body will not feel the fragmented nature of the wood slats which provide support in a single direction, although the deep support will still be felt very firm.
Is it fine to have a high density layer on top of a low density layer? Latex lifespan is proportional with density: low density latex has a shorter lifespan than a high density latex. Lifespan is also reduced by the strength of compression (= force applied over a small area). Since the bottom layer is constantly compressed by the top layer, some people think that it's wrong to put a high density layer on top of a low density layer.
The top layer, on which you sit directly, is compressed only over the area of your body. At the same time, the top layer takes over your direct weight and distributes it on a much wider area, which means that the compression strength of the bottom layer is significantly lower than that of the top layer, which means that its lifespan is higher than if it were the top layer (and directly compressed by your body).
The mattress should have a cover, either for each part for all of them together. The simplest way is to use the original covers, but you could make a custom cover (for the entire mattress). Make sure to not leave the latex exposed, so cover the underside of the mattress, in order to protect the mattress foam from humidity and from breaking into small airborne particles (due to aging).
Over the mattress cover, you should always put a mattress protector or a fitted bedsheet to protect the mattress from body humidity, but also protect the body from the potential flame retardants from the mattress. The protectors with elastic bands at the corners might not stay well in place. Waterproof protectors have a plastic feel to them, and may feel hot during sleep, so use them only if necessary.
Make sure that your bed can support all the weight of all the mattress layers and of the people who will sleep on it.
Remember that the thicker a layer is, the heavier it is and the more difficult it is to maneuver (especially by a single person).
A DIY mattress will be very difficult to turn or flip (because it has several parts and no handles). On the other hand, smaller mattresses can be maneuvered easier than larger mattresses. A full latex mattress can easily exceed 50 kg (110 pounds), so even with a cover with handles it's difficult to maneuver.
The edges of a DIY mattress will be very soft. The possibilities for sex at the edge of the bed will therefore be limited, depending on how much weight will be sitting on the edge.
Don't pull / drag a latex slab because it can break! If you need to move it only a bit, just shake it from a margin or corner, toward that direction. You can also push it, if that's possible.
Do-it-yourself mattress with springs
It's possible to make a DIY mattress which is, on the long term, even more cost and waste efficient than a mattress made from foam layers.
The mattress is for 2 people, and we consider a size of 180 * 200 cm (72 * 80 in).
Mattress structure, from bottom upward:
Preferably, the springs should be pocket springs, to best insulate the motion from each side of the mattress.
There should be no foam inside the spring mattresses, over / under the springs, because foam breaks much faster than springs / steel. You could technically cut the foam out once it breaks, but why bother? Foam on the sides of the spring mattresses is not a problem.
A single 180 * 200 cm spring mattress might be a lot cheaper, so make sure to check.
The firmness of each layer, springs and latex, depends on your preference.
Instead of the latex, it's possible to get a spring topper, like this.
There are various types of bed foundations: solid plank, plank with many small (vertical) holes all over it, adjacent wood boards with many small (vertical) holes along their middle, wood slats, springs.
A bed foundation made made from a solid plank is a bad choice for any kind of mattress because it blocks any ventilation, but it's especially bad for foam mattresses.
A foam mattress should be put on a bed foundation which has good ventilation, like a plank with many small holes all over it, or one which has wood slats.
A mattress should stay on the bed foundation as flat as possible, so avoid putting a mattress on a bed foundation whose slats are spaced at a significantly greater distance than the width of the slats.
A bed foundation which provides support in two (horizontal) directions allows you to use thin mattress without feeling the bed foundation pushing in your back, although the provided support will still be felt very firm. Here are examples of such bed foundations: floor, solid plank, plank with many small (vertical) holes all over it, adjacent wood boards with many small (vertical) holes along their middle, springs.
One of the most common type of bed foundation has wood slats which provide support in only one direction. In order to not feel the fragmented nature of the slats, the mattress has to be much thicker than necessary. If you can feel the slats, if you want to avoid increasing the mattress thickness, put felt or coir / coconut pads on the bed foundation, under the mattress; the thicker the felt / coir is, the more support it will provide; on Amazon, search for "felt mattress pad / protector" or "coir / coconut mattress pad / protector"; alternatively, you use instead a thin mattress made from a firm polyurethane foam.
A bed foundation made with springs is meant to complement a relatively thin mattress. Because the steel of springs is much more durable than the other materials used in a mattress (like foam), when the mattress has to be replaced, the base can be kept, so the replacement cost and waste are significantly reduced.
A bed foundation should allow you to lift the mattress with ease, so make sure that the mattress handles are not covered, and that you have space which allows you to lift and turn the mattress.
The top of the mattress should be high enough so that you can get down from the bed rather than get up from the bed, that is, you should not need to force your knees to raise your body from the bed. An average height is 60 cm (24 in).
Custom bed foundation
If you want to make a solid custom bed foundation, make its legs and the frame which sits on (and around) the legs from wood beams that are 8 * 8 cm (3 * 3 in) thick. Between the bottom of the legs and the frame, put small beams at 45 degrees to provide the legs resistance to longitudinal and lateral movements, like it may happen during sex.
For a 2 people bed, add 2 beams, from head to toe, that are spaced equally along the width of the bed foundation.
In order to provide support for the mattress but still allow it to ventilate, on top of the beams, left to right, put either:
For a 2 people bed, you might want to make the foundation from two pieces instead of a single monolithic one, in order to avoid any risk that it would not fit through some area. Breaking parts of walls is not desirable. Also, the smaller ones are much easier to move.
The pillow is as important as the mattress itself, and should only be chosen in pair with the mattress.
Some pillows are made from blocks of solid latex or memory foam, some are filled with shredded latex or memory foam, while others are filled with various fibers.
For pillows made from solid foam, for people who sleep mostly on their back the pillow thickness should be around 8...12 cm (3...5 in), and for people who mostly sleep on their side the pillow thickness should be around 12 cm (5 in). Some pillows made from solid foam have several layers that can be removed in order to adjust the pillow's thickness to your liking.
For pillows made from shredded foam, some of the foam can be removed in order to adjust the pillow's thickness to your liking. Shredded foam provides stability to the head, and doesn't push back into the nape because the shredded foam compresses fully. Shredded foam lets air circulate among the foam pieces, so it feels cooler than solid foam. The disadvantage of shredded foam is that, unlike a solid block of foam, it has no compression modulus, that is, it immediately compresses all the way and then it feels very firm; give it a few days to adjust to the feeling. If the shredded foam moves toward the back of the pillow, creating a slope that doesn't support the nape anymore, turn the pillow 180 degrees so that the back becomes the front.
If a pillow is made from solid foam, its firmness should be soft or medium. Polyurethane pillows are usually very firm.
Pillows should have two or three cases, one over the other, especially those made from shredded foam. At least two of them should be thick enough so you don't see what's underneath, through any one of them.
A little story about bouncy-foam pillows
For about 8 years I have slept on a latex pillow. The pillow was the most comfortable I ever had, and it had no irreversible deformations; it only got a little yellow and a bit more brittle.
From some point onward, occasionally, I started having extreme neck pain manifesting as hot stabbing flashes when I was turning my head. If the movement was very slow, the pain was dramatically reduced.
After 8 years I've replaced this pillow with a memory foam pillow. The pain virtually disappeared.
I tried again the latex pillow and the pain reappeared the next day. I then realized that the cause of the pain was either: 1) the latex pushing into my nape, or 2) sleeping with my neck twisted because the latex bounciness was forcing me to turn my head in order to find a stable position.
The odd thing was that the latex pillow was much more comfortable than the memory foam pillow when I put my head on it, yet it had an invisible opposite effect on the long term.
I've repeated the experiment with a pillow which had one half made of memory foam and one half made of bouncy foam, and the result was the same: when I was sleeping on the bouncy part, the pain reappeared.
The moral of the story is that if you have neck, back, hip, shoulder or even knee pain, be sure to pay attention to how you sleep, on what you sleep and what is the position of your body for long periods of time on the bed, sofa, chairs, and even toilet (if you sit for long times on it; crouching on it is very bad for the knees).
For instance, if you sleep on your side, on a firm mattress, the hip on which you usually lie may start hurting (even if years later).
A position that you are used to might be bad for your body. Never assume that a comfortable position is a correct position. Because the skeleton is a connected mechanism that acts as a whole, for example, a wrong position on one end of the backbone may have a bad effect on the other end. A too firm, too soft or too worn mattress or pillow may also be the cause of your problems.
Lower back pain can occur because you sit the wrong way on a chair, like with the sole of a foot on the chair, therefore forcing your backbone to bend laterally. You have to sit with your back and neck straight, and with your soles on the ground.
Sitting with the calf or ankle of one foot over the knee of the other (which rests on the floor) may cause pain in the knee of the twisted foot, but also in the calf or ankle of the foot which is resting on the floor.
The biggest problem in understanding the cause of your problems is that the pain will occur much later than the cause. For instance, you may be sleeping in a bad position, but the pain may start occurring only years later.
You could also think that back or neck pain is age related even though it may be your bad posture or mattress / pillow, something to which you may be accustomed and say that it's good for you. Being accustomed to it doesn't mean that it's good for your body, even if it appears comfortable.
Avoid sleeping on your stomach because this position puts great pressure on your neck due to the fact that you need to keep your face turned 90 degrees relative to your backbone (in order to be able to breath).
Generally, the user satisfaction increases as the thickness of the mattress increases.
Your mattress must have a firmness which fits your body, and must not be sagging, that is, it must not have permanently depressed areas (especially where your bottom is).
Don't choose the mattress type based on charts with pressure points. They'll likely show you that memory foam is the best to sleep on, despite the fact that memory foam can't provide support to the body, which means that the pressure of the body will be taken by the support layer below the memory foam, which means that the memory foam is irrelevant in an actual pressure-relieving mattress.
If your back or neck hurts, it may be that your mattress is bad for you, or that your sleeping position is bad. You have to sleep with your backbone straight relative to the ground. If you are used to sleep on your side, the mattress has to be soft so that your hip and shoulder can easily sink in it and therefore allow your backbone to be straight.
A mattress topper should have 5 to 10 cm (2 to 4 inches). More than this would give you an unpleasant sinking feeling because a topper is usually made to provide comfort, not support to the body.
If you use separate mattresses for each person, you may feel the separation between them even if you use a mattress topper. In this case you can use a mattress bridge.
You should buy a mattress only if it has a removable cover so that you can see what the layers inside are, and to be able to wash the cover in order to remove the bad smell released by foam and trapped by the cover.
Over the mattress cover, you should always put a (quilted) mattress protector or a fitted bedsheet to protect the mattress from body humidity, but also protect the body from the flame retardants from the mattress. The protectors with elastic bands at the corners might not stay well in place. Waterproof protectors have plastic feel to them, and may feel hot during sleep, so use them only if necessary.
Oeko-Tex 100 is a certification for the chemical safety of textiles for people.
If you want to sleep well and feel relaxed in the morning then remove stress from your life, do physical exercise, eat properly, and sleep 7...9 hours a day (depending on your body's needs); "sleep" means sleeping, not just lying (consciously) in bed. The muscular tension created by stress can't be reduced by a mattress, no matter how expensive.
I've heard that brand X makes super-mega-ultra great mattresses that make you fall asleep in the showroom as you try one, and have features Y, Z and W that I've heard I really need. Should I buy one?
You know what mattress is good for you? The one that you lie on, and out of the tens that you've tried feels the best to you, fits in your budget and has a warranty which fits your needs (if the manufacturer fulfills that warranty, especially for its inner layers). Keep in mind that, usually, the lifespan is much shorter than the warranty, and it's generally between 5 and 10 years; make sure that you read this about warranties and lifespan.
Also, buy from a manufacturer which describes in as much detail as possible the internal structure of its mattresses, and the materials that they use.
How often should you change the bed linen?
The answer can be vastly different, depending on things like how much do people perspire during sleep, how often do they shower, whether the bed sheet is removed from the bed every morning (and shaken so that dust falls off), whether the duvet has a full cover, and how often are pajamas and pillow cases changed.
You'll read on the Internet advice like changing the bed linen once a week, but washing the bed linen that often is very time and money consuming, and mainly benefits the detergent and bed linen industries.
On average, people change their bed linen after 3 weeks.
How can I ensure that a mattress has Oeko-Tex certification?
Textile manufacturers and their products can have Oeko-Tex certifications. These two types of certifications are different things.
To be certified, a mattress must have a label (with green, orange and black text) stitched on it, label which represents the Oeko-Tex certificate. This label contains the text "Confidence in textiles". If the label contains the text "0904046.O", it means that the mattress is class 2 certified, meaning that it's not expressly certified as being safe for babies.
Oeko-Tex says that in order to get their certification it's required that all the components of an item meet the required criteria without exception (meaning, the outer material, sewing threads, linings, prints, buttons, zip fasteners, rivets).
If you want to verify that a manufacturer is not falsely attaching an Oeko-Tex label to their products, verify that their name is on the Oeko-Text website.
Are metal beds and mattresses harmful to people because they amplify radiowaves?
There is no scientific evidence of this happening.
The people who claim that metal is harmful are using a guest blog article and its linked study (or nothing at all). They usually have something to sell you: foam mattresses, wood beds and even devices that protect you from radiation.
The study itself is only a weak correlation of other studies, not a direct study, and is analyzed here.
A proper study would directly look at how many people sleep on foam and spring mattresses, in the same geographical location, and how many people in each category have cancer.
Also something not accounted by the study is the fact that, from an electrical point of view, modern pocket springs (which are not connected) behave differently than the classic Bonnell springs (which are connected).
For details about correlation in studies, read the Skirts don't cause cancer principle.
Sleep Like the Dead = Information about anything related to sleep, review aggregations.
Most of the companies below sell mattresses through the Internet, which allows them to avoid paying some costs, so they claim to have much lower prices than in a showroom, at the same quality.
DiyMattress = Latex for DIY mattresses. Uses Latexco cores.
EuropeanBedding = Latex mattresses. Great information about mattress. Uses Latexco cores.
John Ryan = Great information about the mattress construction and industry.
Marcapiuma = Blended latex mattresses. Available on Amazon Europe.
SleepingOrganic = Latex mattresses. You can create your own latex mattress from 2, 3 or 4 layers, each either full size or split in half.
Rest Performance = Smart mattresses which use electronics to monitor who sleeps on them, and to adjust their firmness.
Sleep by Number = Smart mattresses which use electronics to monitor who sleeps on them, and to adjust their firmness.
Artilat = Latex core manufacturer.
GommaGomma = Foam core manufacturer.
Latexco = Latex core manufacturer.
LatexGreen = Latex core manufacturer.
Leggett & Platt = Manufacturer of spring cores and toppers.
TalalayGlobal = Latex core manufacturer.
VitaTalalay = Latex core manufacturer.