Article medically reviewed and fact-checked by Dr. Dimitar Marinov (M.D, Ph.D, RDN)
If you’re sleeping on a mattress that’s old, worn out, or otherwise causing you discomfort, you may be wondering what the effects of sleeping on such a ‘bad mattress’ might be.
Sleeping on a bad mattress can lead to back pain, frequent waking, allergies, partner disturbance, overheating, snoring, moodiness, and an increased risk of accidents due to daytime sleepiness.
The rest of this article reveals the 5 signs of a bad mattress and how to fix a bad mattress in more detail.
Alternatively: if you’ve already decided that you need a new mattress, then check out my list of the best mattresses to buy online to find a good one that’s well suited to your sleeping style and requirements.
The 5 Signs of a Bad Mattress
So what exactly is a ‘bad’ mattress?
A bad mattress is one that is sagging, indenting, smelly, noisy, causes pain, and/or otherwise negatively impacts the quality of your sleep.
Here’s a more detailed explanation of each aspect of a potentially bad mattress and how they can affect your sleep:
A sagging mattress is one that displays a pronounced dip of more than 1-1.5 inches in depth across a significant area of the mattress – typically where your body weight is the most concentrated (usually around the regions where your hips and shoulders rest night-after-night).
Mattress sagging typically occurs due to the degradation of the support core (the lower layer of the mattress) but may also arise due to the integrity of the comfort layers becoming compromised through wear and tear.
If you sleep on a saggy mattress regularly then you’re at risk of experiencing back pain due to your muscles and joints being placed in a stressful position for long periods of time.
Mattress indents are concentrated impressions in the upper mattress layers and may lead to discomfort – this can be especially true of a spring mattress because structural defects can cause the springs to be felt more noticeably and lead to sharp pressure points.
A smelly mattress may be caused by the long-term accumulation of sweat and other bodily secretions but this can also be the result of moisture building up on the underside of the mattress (common when memory foam mattresses are placed on the floor or another non-breathable surface/frame in a humid environment).
Sleeping on a smelly mattress can be unpleasant, but also potentially harmful to your health if you’re breathing in mold spores – potentially resulting in allergic reactions, sneezing, a runny nose, rashes, and even asthma attacks .
A ‘noisy mattress’ is more often than not the result of the bed frame being structurally un-sound but if the materials of the mattress have degraded then this can also lead to creaking and groaning when you move around – especially in the case of a spring mattress.
Sleeping on a noisy mattress can cause you to wake up or become annoyed by the sound as you move around – which can be a real issue for autistic sleepers and/or those with misophonia.
5: Pain Upon Waking
If you wake up with aches and pains that tend to wear off as the day progresses – only to return with vengeance the next morning – then this is a strong indicator that your mattress is causing you to sleep in bad posture or is otherwise unsuitable for your body type and/or dominant sleeping position.
For example, a mattress that’s too firm for you can cause pressure points, whilst a mattress that’s too soft may cause you to sink too deeply into the materials and thus cause muscular/joint pain.
A mattress that’s too firm or too soft can arise due to you picking the wrong type of mattress firmness and/or structure relative to your body type and sleeping preferences, or due to your mattress being too old and broken down (with excessive softness and sagging being the most common complaint in such a case).
The 8 Dangers of Sleeping on a Bad Mattress
If you regularly sleep on a bad mattress that’s structurally unsound or otherwise no longer fit for purpose, then you’re at risk of experiencing any of the following 8 issues:
1: Back Pain
A mattress that’s sagging or otherwise unable to keep you in the correct posture whilst also providing the right amount of pressure relief could result in back pain – whilst also potentially aggravating existing medical conditions like sciatica, a slipped disc, or arthritis.
If your current mattress is currently sagging and causing you back pain then you should replace it with a new one that’s the correct firmness for your body type and favored sleeping position, whilst also taking the time to ensure that the mattress has excellent support and pressure relief.
If you already have an existing back pain problem then you might also want to consider pairing your new mattress with an adjustable frame so that you can change the angle of your sleeping surface to find your ideal sleeping position.
Check out my list of the best mattresses and adjustable bed frames for back pain for some excellent options.
2: Frequent Waking
If your mattress is sagging, has indents, is too firm, too soft, is difficult to move around in, or otherwise uncomfortable then you may find yourself waking up frequently during the night due to discomfort.
In the case of subtle discomfort, you may not consciously know that you’re being pulled out of your sleep cycle and instead simply wake up feeling unrefreshed, groggy, and grumpy.
If you’re restless in your current mattress then you should look for a new mattress that provides enough pressure relief so that you’re not experiencing localized discomfort (common in lighter weighted sleepers and those with lower body fat percentages) and also has the right amount of firmness coupled with a responsive and buoyant design so that you can switch positions fluidly without having to exert so much force that you wake yourself up.
Check out my list of the best mattresses for restless sleepers to find the right mattress to help you sleep through the night.
Sleeping on an old mattress that’s packed with dust mites, dead skin cells, dried sweat, and other bodily fluids may lead to the inhalation of allergens that could trigger an allergic reaction or even the worsening of existing conditions like asthma or atopic dermatitis (eczema) .
Simply buying a new mattress may help to alleviate the symptoms of some allergies because the new mattress won’t contain as many allergens.
However, if you have a dust mite allergy, sensitive skin, asthma, or even a latex allergy then I recommend having a look at my list of the best hypoallergenic mattresses for allergy sufferers for some extra protection.
4: Partner Disturbance
If the integrity of your mattress has been compromised through wear and tear then you and your partner may discover that you can feel each other moving around more during the night – which can especially be a problem in a spring mattress (as opposed to an all-foam mattress) because the coils can transfer motion more readily.
If you’re going to buy a new mattress and you and your partner are keen to minimize disturbances then you should either opt for an all-foam memory foam or latex mattress (no springs) because such mattresses are silent and tend to dampen cross-motion and vertical movements very well.
Alternatively, if you want a spring mattress then you should go for a hybrid spring-foam mattress with individually encased coils in the core because they are better at absorbing movements than a fused coil frame.
In either case, you should ensure that your new mattress is placed on a compatible and well put-together bed frame in order to minimize noise and movements even further.
You can find some of the best foam and hybrid mattresses to buy online in my list of the best mattresses in a box.
Aging mattresses may cause you to heat up and feel uncomfortable because as the integrity of the materials degrade over time, the ability for heat dissipation and the throughflow of air lessens.
This can especially be true of memory foam mattresses that naturally tend to retain heat and could thus lead to overheating and night sweats* as the aeration and cooling capabilities of the foam become compromised.
* An important note from Dr. Marinov:
‘If those night sweats are massive and occur even if you fix your bedroom environment it is possible that they are related to a serious conditions such as infections and hematological diseases. Especially if they are coupled with daytime fatigue’.
If you tend to sleep hot then you should go for either a traditional spring mattress or a hybrid spring mattress with natural latex in the top layer for maximum breathability and heat dissipation (the Awara Hybrid is an excellent choice).
But if you want to stick with memory foam, then I advise checking out the Tempur LuxeBreeze from Tempur-Pedic.
If your mattress has become so worn out that it’s altering the angle at which your upper body/head is positioned then you may experience snoring due to your airways being angled differently.
In addition to buying a new mattress with the right firmness, you may also want to consider an adjustable base if you have sleep apnea or tend to snore a lot because elevating the head portion of the bed by as little as 7.5° has been shown to help open up the airways and reduce the effects of obstructive sleep apnea (OSA) .
Check out my list of the best adjustable beds and mattresses to buy together (to save time and money).
Regardless of the way in which your bad mattress is affecting your sleep, one of the proven consequences of sleep deprivation is that of impaired human functioning – with a meta-analysis concluding that mood is the facet most significantly impacted (more so than cognitive or motor performance) .
It’s imperative that you replace your new mattress with one that’s compatible with your physical characteristics and sleeping style – check out the buying guide section of my list of the best mattresses to buy online for detailed guidance.
8: Risk of Accidents
If your mattress is affecting your sleep to the point where you’re experiencing daytime sleepiness then a study concluded that you may be at risk of ‘cognitive lapses’ that could lead to ‘human-error-related accidents’ such as falling asleep at the wheel .
In addition to buying the right mattress and bed frame for your sleeping style, you should also practice good sleep hygiene – which includes winding down, reducing screen exposure before bed, and lowering the room temperature to between 18C and 24C .
4 Ways to Fix a Bad Mattress
Try any of the 4 ways below to fix your bad mattress now:
1: Buy a New Mattress
The most effective way to fix your bad mattress is to buy a new one that’s ideally suited to your body weight, physical characteristics, dominant sleeping position, and takes into consideration any specific medical requirements that you may have.
This is the best solution because uncomfortable mattresses are typically the result of the mattress being too old and/or incompatible with your sleeping requirements.
Check out my list of the best mattresses to buy now where I’ve specifically listed the top mattresses for specific sleeping needs as well as an extensive buying guide that explains how to buy a mattress that’s right for you.
2: Apply a Mattress Topper
If your mattress is too soft, too firm, sagging, or indented and you’re not yet ready to buy a new mattress then you could try buying a mattress topper to adjust the qualities of the mattress.
For example, a firmer mattress topper can help to make a mattress that’s too soft more comfortable and vice versa.
Just be aware that this strategy is like putting a plaster on a broken leg – it doesn’t really fix the underlying issue in a comprehensive way.
3: Use a Hypoallergenic Mattress Cover
If you’re experiencing an allergic reaction with your mattress then you could buy a hypoallergenic mattress cover to put over the top of your mattress and reduce any reactions.
However, I strongly recommend talking to your doctor if you’re experiencing new symptoms of an allergic reaction without explanation so that you can find out the real cause and treat it effectively.
4: Buy a New Bed Frame
If you’re experiencing pain, discomfort, or a noisy bed then you may need to buy a new bed frame or at least repair the one that you currently already have.
Conclusion: Buy a New Mattress
If you’ve read through my list of the 5 signs of a bad mattress and you think that you do indeed have a mattress that’s impacting your sleep quality then I think that the best way to fix your ‘bad’ mattress is to buy a new one.
Click the button below to find a new mattress that’s well suited to your physical preferences and sleeping requirements now.
Sources and References
 NHS – Can Damp and Mould Affect my Health? Accessed 6/11/20.
 Science News – Here’s How Dust Mites Give Dermatitis Sufferers the Itch. Accessed 6/11/20.
 NCBI – The Influence of Head-of-Bed Elevation in Patients with Obstructive Sleep Apnea. Accessed 6/11/20.
 Oxford Academic – Effects of Sleep Deprivation on Performance: A Meta-Analysis. Accessed 6/11/20.
 NCBI – Neurocognitive Consequences of Sleep Deprivation. Accessed 6/11/20.
 NHS – How to Get to Sleep. Accessed 6/11/20.
No part of this article or website is intended to diagnose or cure any medical conditions – always consult with a qualified medical professional before buying a new sleep product or if you notice any health changes.
Image Licencing and Attribution
Main image: ‘Nape Pain’ – by Reklamlar (Getty Images Signature); used with permission as per the terms of the Canva Pro 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.