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This article was written by the site owner – Dan Cartwright – who has been testing and reviewing mattresses and sleep products since 2015.
If your doctor has ruled out any underlying medical reasons for your back pain, then you might be wondering if your back pain is related to your mattress.
As explained in the article I’ve linked to below, a firm mattress can cause back pain, but could a mattress that’s too soft also be to blame?
A soft mattress can cause back pain if it doesn’t provide enough support relative to your body weight and body type because by sinking too far into the mattress materials, your spine and the surrounding muscles are placed under prolonged strain throughout the night.
I know this from personal experience because the first time I slept on a memory foam mattress that was too soft, I ended up with back pain.
I have also tested many mattresses over the years and I often experience the same type of discomfort – especially around my lower back – when the mattress has been too soft and/or not supportive enough.
In the rest of this article, I’ve used my extensive knowledge of mattresses to explain specifically how a soft mattress can cause back pain, how to find out if your mattress is the cause, and how to solve the problem.
Related: click here to find out if a firm mattress can cause back pain.
3 Ways a Soft Mattress Can Cause Back Pain
A compromised support core, uneven surface, and degraded comfort layer can cause a mattress to sag, reduce your night-time mobility, and increase proximity to the firmer support core – potentially resulting in back pain due to pressure points and lying in bad posture.
More details below:
1: Sagging
A sagging mattress is one that exhibits a dip greater than 2 inches anywhere across the surface of the mattress and/or lacks enough support to keep you in good posture.
These dips can arise due to indentations in the materials found in the upper comfort layer of the mattress, or due to a compromised support core that contains broken springs or foam that has lost its ability to provide enough pushback to support your body weight.
Such defects can make the mattress ‘feel’ too soft – meaning that a mattress that was once firm and supportive enough now sinks in too far and can cause you back pain and other discomfort.
However, in this case, the mattress isn’t just too soft – it’s defective – and is no longer suitable for sleeping in due to the health problems it presents.
Sagging is typical of mattresses that are more than 5-7 years old but this can also be an issue for newer mattresses that are defective.
Check out the best anti-sag mattresses that I’ve tested here.
2: Reduced Mobility
A mattress that’s too soft can make it difficult to move around in because the reduced surface tension creates a ‘hammock’ effect where you’re all bunched up.
This can initially lead to back pain due to resting in bad posture – whilst the lack of surface tension can make it harder to move around and get into position that’s comfortable.
This can especially be a problem if you’re a combination or restless sleeper that switches positions often during the night.
You can tell if this is the problem if you’re repeatedly waking up during the night in an uncomfortable position.
Have a look at the top mattresses for restless sleepers that I’ve reviewed here.
3: Contact With the Support Core
If a mattress is too soft in the upper comfort layers to support your body weight, then you may find that you’re sinking too far into the mattress materials to the point where you’re touching the support core below.
This can result in back pain not only because you’re lying in poor posture, but also because the support core tends to be firmer and can create pressure points that may lead to back pain.
This tends to be an issue if you’re a heavier weighted sleeper over 230 lbs and you’re sleeping on a mattress with a relatively thin foam comfort layer – especially if the materials are old and losing their resilience.
The Nolah Evolution is the best mattress that I’ve reviewed for sleepers over 230lbs because it’s 15 inches thick and has a lot of foam in the upper comfort layers.
Click here to see the exact mattress structure in my review.
How to Tell if Your Soft Mattress is Causing Back Pain
If you’re sure that your back pain isn’t coming from an underlying medical condition, then it could be that your mattress is the cause.
Here are 11 things to look out for that indicate that your mattress is too soft and causing your back pain:
1: Your Back Pain is Worse in the Morning and then Eases Off
If you’re waking up with back pain, then this is an indicator that you’re sleeping in poor posture due to your mattress not supporting your body weight adequately – either due to being too soft or not supportive enough.
If your back pain then starts to ease off as the day goes on – only to return the next morning when you wake up – then this further substantiates that the mattress is the cause.
Here are 16 common back pain causes and their solutions.
2: Your Back Pain Starts at Night
In addition to waking up with back pain, if your back starts hurting shortly after you get into bed then this again points to your mattress being part of the problem because it suggests that you’re lying down in bad posture, or the mattress is causing painful pressure points.
If your back pain goes away when you lie on a firmer mattress, then this indicates that the mattress is too soft for you.
Try these 21 ways to sleep better with back pain and sciatica.
3: Your Hips Sink Too Far Into the Mattress
If your hips sink too far into the mattress, this can put pressure on your lower back and cause pain.
This risk increases if you tend to lie on your front, are a heavier weighted sleeper over 230 lbs, and/or you are sleeping on a soft mattress.
Find out more about how a mattress can cause hip pain here.
4: You Wake Up During the Night
If you’re waking up during the night because you are uncomfortable, then this can be the result of a mattress that’s too soft because by sinking into the materials too far, you’re in a position that’s uncomfortable enough to wake you up.
Here are 10 ways to sleep better with upper back pain.
5: It’s Difficult to Switch Positions
If you find it difficult to switch positions – say from your back to your side, or even sitting up in the bed – then your mattress may be too soft for you.
This can impact your sleep quality because not being able to move around in the night easily can result in back pain from being in the same position too long and also cause you to wake up.
Find out if a firm mattress really is better for back pain here.
6: You Feel Smothered
If you feel like your mattress is swallowing you up, then it’s quite likely that your mattress is too soft for you, and this in turn can lead to back pain.
Similarly, if your mattress has deep layers of memory foam in the upper comfort layer, then you may find that you are sinking too far into these materials and this is throwing your posture off – this can be a problem for heavier weighted sleepers that sleep on foam mattresses.
Find out more about memory foam mattresses and back pain here.
7: You Can Feel Weird Pressure Points
A mattress that’s too soft in certain areas – particularly in the upper comfort layers – due to indents or defects can create pressure points on your body that can lead to back pain.
These pressure points can also arise if the comfort and transition layers of the mattress aren’t able to resist your weight, and so you crash into the support core below.
Find out if memory foam is good for side sleepers here.
8: The Mattress Was Surprisingly Cheap
Whilst not every cheap mattress is going to be poor quality, those that are made from inferior quality materials are going to be more prone to sagging and softening prematurely, which can lead to discomfort and back pain.
The SweetNight Twilight is an example of a cheaper mattress that’s still good quality.
9: Your Mattress is Sagging or Has Indents
Mattresses that are sagging can feel too soft because the support core is compromised, whilst mattresses that have indents can feel soft in places with raised up parts that are harder.
This can cause back pain by putting you in bad posture and creating pressure points.
Here are 3 ways that your old mattress is causing you back pain.
10: The Mattress is New
Whilst new mattresses typically feel too firm and then soften up as time goes on, you may feel that your new mattress is too soft if you’ve just switched from a firmer spring mattress to one that has memory foam in the upper comfort layer.
Based on my experience of testing mattresses, I have found that whilst it can take up to 30 nights of continuous use for the materials to adjust to your body type, most of the adaptation takes first in the first week.
This is why it’s important to buy a mattress with a sleep trial that last longer than 30 nights so you can return it if you don’t like it.
Click here to see the best mattresses I’ve tested with long sleep trials.
11: The Mattress is More Than 5-7 Years Old
Despite what many mattress companies would have you believe, most mattresses need replacing after around 5-7 years.
After this period, the risk of them softening up to the point where you are in bad posture and experiencing back pain increases as time goes on.
If your mattress is more than 5-7 years old and you have back pain, then buying a new one is likely the best solution.
Click here to see the best mattresses to buy now.
How to Stop a Soft Mattress From Causing Back Pain
The most effective way to stop a mattress that’s too soft from causing you back pain is to apply a firm/zoned mattress topper; place the mattress on a compatible frame that has good support; avoid sleeping on your front and instead sleep on your back; or replace the mattress completely for a more suitable one.
More details below:
1: Sleep On Your Back (Not On Your Stomach)
If your mattress is too soft for you, then sleeping on your front is the worst position to be in because this puts a lot of pressure on your lower back and can cause pain.
Sleeping on your side isn’t quite as precarious, but sleeping on your back is the best position because this puts you in a stable position.
However, if your mattress is sagging or very soft, then this might not remedy the issue – in which case you should take steps (as outlined below) to make the mattress firmer, or simply buy a new mattress that’s the correct firmness.
Click here to find out how to stop your mattress from causing shoulder pain.
2: Attach a Firm Mattress Topper
If your mattress is only slightly too soft, then purchasing a firm mattress topper can solve the issue.
Mattress toppers are as they sound – an additional section of material that you can attach to the top of your mattress to change the firmness and feel.
However, not all firm mattress toppers feel the same.
For example, a latex foam mattress topper will typically have more pushback and bounce to it than a memory foam mattress topper.
Go for a memory foam topper if you want deeper pressure relief, but if you have back pain that’s aggravated by sleeping on a surface that’s too soft, then latex foam or traditional batting is likely the better option due to its more resilient feel.
You can also get mattress toppers with a ‘zoned’ arrangement – where the middle third is firmer than the other two thirds – which can help to alleviate your back pain by providing more support around your hips and lower back.
3: Use a More Supportive Frame
Sometimes, a mattress can feel too soft because it’s resting on a bed frame or surface that’s not supportive.
In many cases, putting an otherwise healthy mattress on a compatible frame can help to stop the support core from sagging.
In general, slatted frames with slats that are no more than 3 inches apart and solid platform frames are the most supportive – although good quality adjustable frames are also an option.
The least supportive frames are typically those with a mesh base that lack proper structural support.
Most high quality mattresses these days don’t need to be placed on a box spring – and some mattresses can also be placed directly on the floor.
Click here to see the best mattresses that don’t require a box spring.
4: Swap or Flip the Layers
Latex mattresses often have individual, non-fused layers that can be swapped around.
Similarly, some mattresses specifically come with dual firmness settings so that you can pick and choose.
For example, the Mend Adapt has a flippable comfort layer that allows you to choose between firm and soft as you see fit.
Click here to see my full Mend Adapt review.
5: Replace Your Mattress
If your mattress is structurally damaged, sagging, or otherwise too soft to the point where it can’t be fixed with a firm mattress topper or other adjustment – then you should consider replacing your mattress.
If your mattress is still under the terms of its sleep trial, then you can return it for either a variation that is better suited to your body type or a full refund.
Click here to see my top mattress recommendations.
How to Buy a Mattress That Won’t Cause Back Pain
The most effective way to avoid back pain caused by a mattress that’s too soft is to select the correct level of firmness; choose a hybrid design with zoned support; ensure the material type is suited to your needs; and pair the mattress with a compatible adjustable base.
Instructions on how to do this are listed below:
1: Select the Correct Firmness
Selecting a mattress with the correct level of firmness relative to your dominant sleeping position, body type, and body weight is the most significant step that you can take to ensure that your new mattress doesn’t cause you back pain due to it being too soft.
Choosing the right firmness isn’t an exact science, but the table below can help to reduce the chance of you ending up with a mattress that’s either too soft or too firm (the vast majority of sleepers will feel comfortable in a medium or medium-firm mattress):
| Firmness | Suitability |
| Extra-soft | Side sleepers <130 lbs |
| Soft | Side sleepers 130 – 150 lbs |
| Medium-soft | Side sleepers 150 – 180 lbs |
| Medium | Front, back, side sleepers 150 – 200 lbs |
| Medium-firm | Front, back, side sleepers 150 – 230 lbs |
| Firm | Front + back sleepers 200 – 230 lbs |
| Extra-firm | Front + back sleepers >250 lbs |
2: Choose a Hybrid Design
A hybrid mattress consists of a spring core and either memory foam, latex foam, polyfoam, or traditional materials in the upper comfort layer.
A high quality hybrid mattress with a pocket coil core and quality foam comfort layer in the right firmness for your body type is the best way to ensure that you’re able to sleep in good posture without experiencing painful pressure points.
Learn more about hybrid mattresses here.
3: Select the Right Materials in the Comfort Layer
Beyond the firmness, the materials that go into the upper comfort layer will also play a role in how comfortable you are in your mattress.
It’s a common misconception that just because the mattress contains foam, it will be soft.
This is because the firmness is set independently of the materials – so you can have both firm and soft foam mattresses.
However, certain types of foams will sink in more than others – so this is an important consideration, especially if you have back pain and are on the heavier side.
The table below can help to guide you in regards to choosing the best type of foam to have in the upper section of the mattress:
| Material | Qualities |
| Memory foam | Excellent pressure relief but compresses the most and can trap heat. |
| Latex foam | Good pressure relief – not as good as memory foam – but is more bouncy and breathable. |
| Polyfoam | Provides reasonable pressure relief and support if the density is high enough. |
4: Pick a Mattress With Zoned Support
A mattress with zoned support has a firmer middle third when compared to the upper and lower third.
This is desirable because it can provide extra support for your lower back whilst providing more pressure relief and ‘give’ on the more prominent regions of your body like your shoulders.
A mattress with a zoned support core can be the ideal choice for side sleepers with back pain – with the Nolah Evolution being the best mattress with zoned support that I’ve personally reviewed.
Click here to see my full review.
5: Pair Your Mattress With an Adjustable Base
Putting your new mattress on a compatible adjustable frame allows you to adjust the positioning of your sleeping surface in order to find the exact angle that gives you the most comfort.
Adjustable beds are brilliant for helping with back pain, acid reflux, snoring, and other conditions like COPD.
Click here to see the best adjustable beds I’ve reviewed.
Image Attribution and Licensing
Main image: ‘Young woman sitting on bed suffering from back pain’ by westend61 used with permission under the terms of Canva’s One Design Use License Agreement.
Dan is the founder and head content creator at Bedroom Style Reviews.
He has been working as a professional online product reviewer since 2015 and was inspired to start this website when he ended up sleeping on a memory foam mattress that was too soft and gave him backache.
Through in-depth research and analysis, Dan’s goal with this website is to help others avoid such pitfalls by creating the best online resource for helping you find your ideal mattress, bedding, and bedroom furniture.
Dan is a qualified NVQ Level 2 Fitness Instructor with 6 years’ experience helping clients improve their health through diet, exercise, and proper sleep hygiene.
He also holds several college and university-level qualifications in health sciences, psychology, mathematics, art, and digital media creation – which helps him to publish well researched and informative product reviews as well as articles on sleep, health, wellbeing, and home decor.
Dan also has direct personal experience with insomnia, anxiety, misophonia (hypersensitivity to sounds), and pain from both acute and long-standing sporting injuries – he enjoys writing insightful articles around these subjects to help fellow sufferers of such conditions.
Learn more about Dan here.