Article medically reviewed and fact-checked by Dr. Dimitar Marinov (M.D, Ph.D, RDN).
You may have heard that a firm mattress is better for back pain, whilst other sources may say that a firm mattress can actually cause back pain.
However, the real answer depends on the characteristics of the individual:
A firm mattress can cause back pain in lighter individuals under 150 lbs (especially side sleepers) due to increased pressure points, greater compression forces, and poor posture; whilst heavier weighted front and back sleepers over 230 lbs may experience reduced back pain due to better posture.
The rest of this article explains in detail how a firm mattress can specifically cause back pain, whilst also revealing which mattress firmness is likely to help alleviate or prevent back pain relative to your physical characteristics and dominant sleeping position.
I’ve also listed the 4 signs that indicate that your mattress could be the cause of your back pain along with 5 ways that you can make your firm mattress softer to help you potentially alleviate discomfort.
Alternatively: if you’d like to buy a new mattress to help lessen or prevent back pain then have a look at my list of the best mattresses and beds for back pain (it’s been medically reviewed and fact-checked by Dr. Dimitar Marinov M.D, Ph.D, RDN for accuracy).
How Can a Firm Mattress Cause Back Pain?
Mattress firmness is a setting configured by the manufacturer that influences how ‘hard’ or ‘soft’ a mattress is likely to feel when you lie on it.
However, the final firmness, feel, and overall comfort level will depend on how your individual body weight, body type, and dominant sleeping position interact with the mattress.
This means that a ‘firm’ mattress will typically feel softer to heavier weighted sleepers over 230 lbs who sleep on their back or front, whilst a firm mattress is likely to feel even firmer the lighter you are (especially if you weigh less than 150 lbs) and sleep on your side (since you will tend to lie more ‘on’ the materials and so your more prominent shoulder and hip regions will be put under more pressure).
Furthermore, back pain can have many causes and is highly dependent upon your individual circumstances and medical conditions.
All of this variability, subjectivity, and uncertainty means that it’s NOT accurate to make the sweeping generalization that a firm mattress causes back pain, nor would it be fair to say that a firm mattress is automatically the best choice if you have back pain.
For example, Eileen Vollowitz, BS, PT – a physical therapist specializing in orthopedics and occupational health who is the founder of Health by Design (a manufacturer and distributor of ergonomic furniture) – says that the traditional medical advice of sleeping on a firm mattress may help some individuals but also harm others; potentially exacerbating lower back pain .
Therefore, I personally feel that it’s more accurate to say that a mattress that’s TOO firm for you relative to your physical characteristics is more liable to cause you back pain than a firm mattress that’s correctly aligned with your needs.
Based on my own experience of sleeping on mattresses with different firmnesses and what I know about mattresses in general, here are the 3 primary ways that sleeping on a mattress that’s too firm for you could cause back pain:
1: Bad Posture
If you sleep on a mattress that’s too firm for you, then this could prevent you from sinking far enough into the mattress to allow your spine to align correctly and remain in the correct posture.
This could lead to upper, mid, or lower back pain as well as a restless night’s sleep due to the discomfort and from your muscles and nervous system being overstimulated as they try to fight the forces being placed upon them.
Lighter weighted sleepers under 150 lbs are more likely to experience back pain derived from poor posture as a result of sleeping on a mattress that’s too firm because you’ll naturally tend to rest more on top of the mattress which can prevent a healthy amount of material sinkage.
2: Pressure Points
If you sleep on a mattress that’s too firm for you then you may experience an increase in pressure points that may aggravate existing back pain conditions like sciatica because the lack of ‘give’ in the surface material may increase the pressure on the herniated disc, bone spur, or other physical abnormality that’s already pinching your sciatic nerve and thus compound the problem .
Sleepers with a lower body fat percentage could be the most at risk of this type of pressure-based back pain due to the more angular regions of your body naturally being more susceptible to pressure.
However, when it comes to sciatica and back pain, sleepers of all weights could experience this type of discomfort on a mattress that’s too firm for them.
3: Compression Forces
Sleeping on a mattress that’s too firm for you may also increase the amount of pressure being placed on your joints which could exacerbate existing back pain conditions like arthritis or sciatica – or cause new pain due to worsened posture because you’re not sinking far enough into the materials to allow the compression forces to be dissipated into the materials of the mattress.
Again, lighter weighted sleepers under 150 lbs are potentially the most likely to experience this type of discomfort when sleeping on a mattress that’s too firm for them due to the natural tendency to lie on the materials rather than sink in.
Which Mattress Firmness is Best for Back Pain?
A scientific study concluded that a medium-firm mattress outperformed a firm mattress in terms of reducing back pain whilst in bed, upon rising, and throughout the day for 313 adults tested over a 90-day period .
However, this study doesn’t mean that everyone with back pain should buy a medium-firm mattress because back pain is a highly individualized condition, and the most suitable mattress firmness is dependant on a range of subjective factors.
The best mattress firmness for back pain could be soft, medium, firm, or another firmness variant depending on your body weight, body type, and dominant sleeping position.
This can make choosing the right mattress firmness for your back pain challenging.
And even if you consult your doctor first (which is the first thing that you should do before buying a sleep product for your health needs), you may still be unclear on the most suitable mattress firmness to help with your back pain.
That’s why I’ve put together a list of the different mattress firmnesses and provided some guidelines as to which setting is typically best suited to the different combinations of body weights, body types, and sleeping positions to provide some clarity.
Mattress Firmness Suitability For Back Pain
Mattresses can potentially be available in any of the following firmnesses (although most manufacturers typically limit their selections to the soft to firm range since the extra-soft and extra-firm options aren’t in great demand).
Extra soft mattresses are typically best for side sleepers that weigh less than 130 lbs because they allow you to sink more deeply into the mattress materials to remove pressure on your hips and shoulders.
This means that an extra-soft mattress may be suitable if you have back pain that’s primarily triggered by surface pressure – such as sciatica or nerve-related back pain – because the softer surface is less liable to create pressure points.
Soft mattresses are often preferred by side sleepers and lighter weighted sleepers under 150 lbs – again due to the greater ‘give’ afforded by the upper comfort layers that may also provide relief for back pain that is brought on through pressure points.
Softer mattresses are often best avoided by heavier weighted sleepers over 230 lbs – especially if you sleep on your front – because you’re more likely to sink into the mattress and experience back pain due to spinal misalignment and bad posture.
Medium-soft mattresses are often enjoyed by side and back sleepers in the 130 – 230 lbs range, whilst front sleepers under 200 lbs who prefer more pressure relief may also feel well supported.
A medium firmness mattress is the most popular mattress firmness and is typically best suited to front, back, and side sleepers in the 130 – 230 lbs range (which is thought to be around 80% of sleepers).
If you have back pain and fall into this range, then a medium mattress with a good support layer and an adaptive memory foam or latex foam top layer could be ideal for you.
A medium-firm mattress offers a touch more firmness that may be beneficial for front and back sleepers in the 130 – 230 lbs range that require more surface tension to help keep their hips in proper alignment to guard against back pain.
If you’re a side sleeper then you may also enjoy the firmer feel if you’re in the 200 – 230 lbs range because the increased pushback may help to offset your body weight to maintain good posture without increasing the pressure in your shoulder and hip joints too much.
A firm mattress is typically best suited to front and back sleepers heavier than 230 lbs because the increased surface tension may help to stop you from sinking too far into the mattress.
Therefore a firm mattress could be a good choice for you if your back pain is related to poor posture when lying down rather than surface pressure.
Extra-firm mattresses are best suited to the heaviest front or back sleepers over 250 lbs because the maximal surface tension can help to stop you from sinking into the materials too much and causing bad posture and back pain.
Some ‘orthopedic’ mattresses may be classified as extra-firm, but it’s important to note that there are no official regulations that make orthopedic labelled mattresses any better at combating back pain than mattresses with a different level of firmness .
How to Tell if Your Mattress is Causing Back Pain
If you’ve recently started to develop back pain then you should go and see your doctor to see if you can pinpoint the exact cause of your back pain and then devise a suitable treatment plan.
However, if one or more of the following conditions are true then it could point to your mattress being the source of your back pain:
1: Morning Pain
If you wake up with a stiff back or pain that tends to lessen as the day goes on – only to return the next morning – then it could be a sign that your bed is putting you in poor posture or increasing the pressure points on your body and leading to back pain.
2: The Mattress is New
If you’ve just bought a new mattress then it can take up to 30-60 nights of continuous use for the mattress to ‘break-in’ and adjust to your physical characteristics and dominant sleeping position.
It’s common for back pain to arise during this adjustment phase and should pass once the materials have adapted to your body shape (typically within the first 7 days).
However, if the mattress is still causing you discomfort after the first 1-2 months then the mattress may not be suitable for you and you may be able to return it under the terms of the sleep trial.
That’s why I always recommend buying a mattress with a long sleep trial that lasts for at least 3 months so that you can return the mattress if you don’t like it with minimal hassle.
3: Visible Sagging
If your mattress is visibly sagging (typically more than 1.5 inches) then this could be contributing to your back pain by putting you in a bad posture that’s placing an ongoing strain on your muscles and joints.
If you’re unsure if your mattress is sagging, then you can use the technique in the video below to locate the regions that are sagging and measure their depth accurately (some sagging mattresses can be replaced or repaired under the terms of the warranty if there’s a defect, or under the terms of the sleep trial if it’s still effective):
4: The Mattress is More than 7 Years Old
Most mattresses tend to have an average expected lifespan of around 5-7 years with the correct care, whilst some of the best quality hybrid and latex foam anti-sag mattresses could last up to 10 years or more.
So if your mattress is more than 7 years old then it could be that your back pain is being caused by a worn-out support core, sagging top layer, and/or uneven upper surface.
In which case you should check out the upcoming section that walks you through the process of buying a new mattress to combat back pain.
5 Ways to Make a Firm Mattress Softer
If your new or existing mattress is currently too firm for you and causing back pain then here are 5 things that you can do to make it softer and potentially more comfortable.
1: Controlled Pressure
New mattresses tend to be quite stiff because the materials haven’t yet been exposed to your body weight.
Therefore, in addition to sleeping on the mattress every night for at least 30 nights to break in the materials, you can encourage the fibers to relax by applying gentle pressure across the entire surface area of the mattress.
I don’t recommend standing on the mattress because this could cause damage to the materials (especially if the top layer is made from memory foam).
Instead, use your hands to massage the materials gently or roll on the mattress if you want to save time (try 10-30 minutes daily for up to 30 days).
The application of controlled pressure can also help you to make your new memory foam mattress expand fully.
2: Increase the Ambient Temperature
In addition to applying pressure, you can potentially make a new memory foam mattress softer by increasing the ambient room temperature to 20°C (68 °F) or more.
However, don’t apply a localized heat source like an electric blanket or hot water bottle since this may damage the foam.
3: Change the Foundation
Placing your new mattress on a box spring or a slatted wooden base can help the mattress to have more ‘give’ to it and make it feel softer.
This contrasts with putting your mattress on the floor or a solid platform base which tends to make it firmer.
4: Buy a Soft Mattress Topper
Mattress toppers are a convenient way to change the firmness of your mattress – placing a soft mattress topper on top of your firm mattress may help to alleviate pressure-based back pain.
5: Layer Exchange
If your new latex foam mattress is too firm for you then in addition to potentially returning it under the terms of the sleep trial, the company that you bought it from may be able to offer you a ‘layer exchange’ – where instead of replacing the entire mattress, they send you a new comfort layer with a different firmness to improve the comfort.
How to Buy a Mattress to Combat Back Pain
If you’ve decided that you need to buy a new mattress then you can follow the 5 steps below or head to my page with the best mattresses for back pain (medically reviewed by Dr. Dimitar Marinov M.D, Ph.D, RDN) to save yourself some time (and money if you buy through the links on that page to secure limited-time discounts):
1: Talk to Your Doctor
Before buying any sleep product to help with your back pain, you should consult with your doctor to first find out the root cause of the issue, devise a treatment plan, and ask them if a new mattress is the way to go.
If so, then you can apply the following steps to help you find the most suitable mattress for your needs.
2: Choose a Hybrid Design
A high-quality hybrid mattress is typically the best type of mattress for back pain because the individually wrapped springs can provide adaptive support for your spine to maintain good posture, whilst the foam top layers can help to soften pressure points that may otherwise aggravate your nerves and impede circulation.
If maximum pressure relief is your goal, then a memory foam topped mattress is the best choice, whilst natural latex foam can provide a more breathable alternative if you tend to sleep hot.
3: Select the Firmness
It’s crucial that you choose the right mattress firmness based on your body weight, body type, and preferred sleeping position – use the list that I gave you earlier to help you find the right option for you.
4: Look For Zoned Support
Some mattresses like the Level Sleep mattress offer zoned support or zoned firmnesses so that you can experience more support around your lower back and greater pressure relief around your shoulders and head.
This can help to promote better posture and reduce pressure more effectively when compared to a mattress that has the same amount of support/firmness across the entire surface area of the mattress.
5: Consider an Adjustable Base
One study found that switching from an innerspring bed to an adjustable bed resulted in a ‘32% pain decrease and a 73% increase in sleep quality’ amongst the participants who were suffering from chronic back pain .
And there are many anecdotal reports that sleeping on an adjustable bed with a suitable mattress can help to reduce lower back pain and ease the symptoms of conditions like GERD/acid reflux and sleep apnea (including snoring).
Here are the concise answers to some of the most common questions related to firm mattresses and back pain.
Can a Bad Mattress Cause Body Aches?
A mattress that’s too firm, too soft, sagging, or otherwise unsuitable (‘bad’) can cause body aches and pains by placing stress on your body and causing you to lie in a bad posture for prolonged periods.
Are Firm Mattresses Good for Your Back?
A firm mattress can be good for your back if this level of firmness is suitable for your physical characteristics – with heavier weighted front and back sleepers over 230 lbs often experiencing the added support and surface tension that they require to maintain good posture and avoid back pain.
Why Does a Firm Mattress Hurt Your Back?
A firm mattress can hurt your back by forcing you into a bad posture, increasing pressure points on your body, and increasing the internal compression forces in your joints to create new back pain or exacerbate existing back pain conditions.
How Do You Know if Your Mattress is Too Firm?
You can tell if your mattress is too firm for you by noticing the pressure points that it creates on your body and by looking for gaps under your lower back where the materials aren’t allowing you to sink far enough into the materials.
Conclusion: The Ideal Firmness for Back Pain Varies
It’s incorrect to say definitively that a firm mattress is either good or bad for back pain – both instances can be true depending on the physical characteristics of the individual and the root cause of their back pain.
What is the Best Mattress For Back Pain?
The best mattress for back pain is the one that fits your personal requirements as closely as possible – which may be best achieved through the combination of a suitable mattress and an adjustable bed frame.
Click the button below to find out my #1 mattress and adjustable bed combination for back pain now.
Sources and References
 Healthy By Design (HealthyDesign.com) – Furniture Prescription for the Conservative Management of Low-Back Pain. Accessed 4/10/20.
 Mayo Clinic – Sciatica. Accessed 4/10/20.
 Science Direct – The Lancet: Effect of Firmness of Mattress on Chronic Non-Specific Low-Back Pain: Randomised, Double-Blind, Controlled, Multicentre Trial. Accessed 4/10/20.
 Wikipedia – Orthopedic Mattress. Accessed 4/10/20.
 Europe PMC – Short-Term Outcomes Of Chronic Back Pain Patients On An Airbed Vs Innerspring Mattresses. Accessed 4/10/20.
Image Attribution and Licencing
Main image: Woman With Back Pain at Home in the Bedroom – WaveBreakMedia (Getty Images) used with permission via Canva’s One Design Use License Agreement.
No part of this article or website provides medical advice – please consult with a qualified medical professional for such guidance.
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.