Sleeping positions: what each one requires from the mattress and pillow
By the Morfeo sleep equipment team, mattress and pillow manufacturers in Yecla (Murcia) · Updated in September 2026
Quick answer
There is no single best sleeping position for everyone. Side sleeping is best for most people and the only position that helps with pregnancy, acid reflux, or snoring; sleeping on your back is the most neutral for your spine but the worst if you snore; sleeping on your stomach puts the most strain on your neck and is the only position that should be changed. And what really determines whether your sleeping position is comfortable is not the position itself: it is whether your mattress and pillow support it. The same position on the wrong equipment will still cause pain.
In this guide
Almost everything written about sleeping positions ends up on the same list: side sleeping is good, stomach sleeping is bad. The problem is that this list is practically useless, because no one consciously chooses how they sleep. Your sleeping position is the last thing you do before falling asleep and what your body does on its own during the next seven hours.
What is useful is something else: knowing what your sleeping position requires from your mattress and pillow, and checking whether yours are providing it. That is where there is real room for improvement, and it is something that is almost never published with figures.
The four sleeping positions and how each affects your back
| Position | Pros | Cons |
|---|---|---|
|
Side sleeping The most common |
Keeps the airway open, reduces snoring and acid reflux, and is recommended during pregnancy (on your left side) | Concentrates your weight on your shoulder and hip. If the mattress does not give in these two areas, pressure points will appear |
| Back sleeping | Distributes your weight across the entire surface and leaves your spine in its most neutral position | This is the position in which snoring is most common and sleep apnea worsens, because your tongue falls backward |
| Stomach sleeping | May slightly reduce snoring | Forces you to turn your neck almost 90° all night and causes your lower back to sag. It is the only position that should be changed |
| Very closed fetal position | Comfortable and protective, it relieves lower back pain in many cases | Completely closed, with your knees to your chest, it restricts breathing and strains your neck |
Notice that none of the "cons" refers to the position itself: it refers to what happens when the surface does not support it. A mattress that does not allow your shoulder to sink makes side sleeping a bad position. A pillow that is too high makes back sleeping a bad position.
What each position needs, in numbers
This is the part that makes the difference, and the one you will rarely see published:
| If you sleep | Mattress firmness | Pillow height | Why |
|---|---|---|---|
| On your side | Medium or medium-firm | 14–18 cm | The mattress must allow your shoulder and hip to sink in; the pillow must fill the gap between your ear and shoulder |
| On your back | Medium-firm or firm | 10–13 cm | It must support the curve of your lower back without letting your hip sink, and the curve of your neck without pushing your chin up |
| On your stomach | Medium-firm or firm | Less than 10 cm | The less your hip sinks and the lower your head is, the less strain is placed on your lower back and neck |
| You change positions a lot | Medium | Medium | The one that is least compromising for the two positions you repeat most |
In the Morfeo range, these heights are listed on every product page: the AirHigh® is 18 cm, the SojaVisco® is 13 cm, and the Calma is 12 cm. We state this because it is the figure that makes the difference, and almost no brand lists it: you will see "ergonomic support" or "extra height," but not the centimeters.
The thirty-second test
Lie down in your usual position and ask someone to take a photo of you from the front, at bed height. The line from the back of your neck to the middle of your back must appear straight. If your head appears higher than your shoulder, your pillow is too high. If it appears sunken toward the mattress, you need a higher one. And if your hip sinks when you are on your side and a downward curve appears, the mattress is the problem, not the pillow.
Sleep posture hygiene: five habits
Sleep posture hygiene is the set of habits that protect your spine day to day, and at night it comes down to five:
- Spine in line: in any position, the back of your neck, your back, and your hip must be in a straight line, without your head drooping or your hip sinking.
- Support where needed: a pillow between your knees if you sleep on your side; a cushion under your knees if you sleep on your back.
- A pillow at the right height: the one your position requires, in centimeters (see the table above), and that does not flatten when you rest your head on it.
- A mattress that does not sag: if it gives way in the hip area, no position will be comfortable. In the Morfeo range, medium firmness is the Nature; medium-firm, the Altus; firm, the Original Hybrid, the VisCool, and the XL.
- Get in and out of bed as a whole: on your side, turning your shoulders, hips, and knees at the same time and using your arms for support, without twisting your torso.
You can change your sleeping position, but not during the night
If you sleep on your stomach and want to stop, you will not achieve it through willpower when you go to bed: as soon as you fall asleep, your body will return to its usual position. What does work is making it uncomfortable to turn over:
- Start on your side with a pillow between your legs. It keeps your hip aligned and acts as a physical barrier. This is the change that most people manage to maintain.
- Put a long pillow against your chest. Hugging it takes up the space you would otherwise turn into.
- Lower your head pillow. While you are changing, the flatter it is, the less strain it will put on your neck on the nights you still end up sleeping on your stomach.
- Give it three or four weeks. For the first few days, you will wake up on your stomach. Count the nights you do not, not the nights you do.
And an honest caveat: if you sleep on your stomach and wake up feeling perfectly fine, do not change anything. A sleeping position that does not cause you problems is not a problem.
From 12 to 18 cm, memory foam made in Spain. Choose based on the centimeters your position requires, not the adjective.
Two answers
What do you need?
What position do you spend most of the night in?
Do you wake up with discomfort?
If you sleep on your side with discomfort, the cause is clear: if your shoulder or hip hurts, the mattress is not allowing them to sink in and is creating a pressure point. If your neck hurts, it is the pillow, and you need 14–18 cm.
When sleeping on your back, the discomfort in your neck upon waking usually comes from a pillow that pushes your chin toward your chest. If it is your lower back that hurts, then it is the mattress: your hip is sinking.
If you sleep on your stomach with discomfort, this is the only case in which the position is the cause and not the symptom. Lower the pillow to the minimum and start turning onto your side with a pillow between your legs.
If you change positions a lot and wake up feeling bad, the problem is usually that your equipment is optimized for a position you only use half the night. Medium firmness and a medium-height pillow are the least compromising for the two positions you repeat most.
Sleeping on your side without discomfort means that your mattress and pillow are providing what that position requires. Measure the height of the pillow before it wears out: that is the figure you will use when buying the next one.
Sleeping on your back without discomfort is the most neutral combination for your spine. The only thing to watch over time: that the mattress does not start to sag at the hip, which is where it shows first.
If you sleep on your stomach without discomfort, there is no need to change it. Keep the pillow as flat as possible, which is what prevents it from starting to hurt, and watch your neck over the months.
Changing positions and waking up feeling good means that your equipment is neutral enough for the two or three positions you repeat. When you renew, do not go to the extremes of firmness or height.
These are general guidelines about rest. If the pain is persistent, wakes you up at night, or goes down your arm or leg, consult a healthcare professional.
Frequently asked questions
What is the best sleeping position?
There is no single best one for everyone. Side sleeping is best for most people and the only one that helps with acid reflux, snoring, and pregnancy. Back sleeping is the most neutral for your spine, but the worst if you snore. Stomach sleeping puts the most strain on your neck.
Is sleeping on your stomach bad?
It is the least recommended position because it keeps your neck turned almost 90° all night and causes your lower back to sag. That said, if you sleep this way and wake up without discomfort, there is no need to change anything.
What position is best for back pain?
For the lower back, on your side with a pillow between your legs, or on your back with a thin cushion under your knees. Both reduce tension in the lower back. But before changing your position, it is best to check the mattress: if it sags at the hip, no position will compensate for it.
What if I change positions during the night?
This is normal: almost everyone changes several times. In that case, do not optimize for a single position; look for medium firmness and a medium-height pillow, which are the least compromising for the two positions you repeat most.
Can you change your sleeping position?
Yes, but not through willpower: you must put up a physical barrier. Starting on your side with a pillow between your legs and another hugged to your chest is what most people manage to maintain. Allow yourself three or four weeks.
What position is recommended during pregnancy?
On your side, preferably on your left side, with a pillow between your knees and another for support under your abdomen. From the second trimester, sleeping on your back is not recommended. For any specific questions, consult your midwife or doctor.
Does the position or the mattress have more influence?
The mattress and pillow, in most cases. Your body chooses the position; what you decide is the surface on which it does it. A good position on a worn-out mattress will still hurt.
Mattresses that support your position
Pocket springs and latex made in Yecla (Murcia). 100 nights to try and a 10-year warranty.
