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Sagging Mattress vs Body Impressions: (Differences & How to Fix)

After having a mattress for a while, you’ll notice that it begins to change shape, especially if it’s older.

This change in shape can be due to many things, but the most common cause is either that the mattress has begun to sag, or the mattress has simply taken an impression of your body in your most comfortable sleeping position, so you’ve essentially molded your mattress to fit you. 


Body impressions are natural and can sometimes actually help promote spinal alignment, but a sagging mattress is not helpful or healthy for you.

So how can you tell the difference between these two kinds of mattress dents? Keep reading to find out! 

The Causes : Body Impression or Sag?

There are two main causes of dents in a mattress: natural compression (body impression) and the disintegration of a mattress’s components (sagging). 


A body impression may become apparent after only two or three nights of sleeping on the mattress, and it will present itself in the form of small dents on the surface of the mattress.  

On the other hand, sagging is something that develops over time, though how long it takes varies depending on how old the mattress is and the materials used in the construction. It’s possible for the springs in a mattress to grow less taut, or for the foam interior to become more pliable.

A Sagging Mattress

A sagging mattress is not healthy for either your sleep or your body.

You can tell that your mattress is sagging rather than dented because it will collapse in the middle and will not provide the appropriate support that’s necessary for a comfortable night’s sleep.


If your mattress is sagging, flipping it over may provide you with some temporary relief; nevertheless, keep in mind that modern mattresses are designed to survive without the need for the owner to flip the mattress (unless you buy a double-sided mattress).

This is because the bottom layer of mattresses serves as the support layer and does not contain the comfort components that are found in the top layer of the mattress.

If you have already formed a body impression on the surface of your mattress, then this is another reason to avoid flipping it. 

If you accidentally buy the improper mattress for your body type, sleeping position, and weight, then your mattress may start to droop before its time.

Other factors that can affect mattress sag include weight and position while sleeping.

Because of this, it’s very important to ensure that you are purchasing the appropriate mattress for your specific requirements when you are sleeping. 

As anyone who’s bought a mattress knows, these products don’t come cheap.

But with that higher price comes higher quality, and if you’re going to be sleeping on something for years, you don’t want to spend every night of that being uncomfortable.

Because of this, it’s important not to skimp on mattress support. 

Do New Mattresses Sag?

No, there should be no reason for a new mattress to sag, although in very rare cases it could begin to sag quickly if your bed frame is broken, as it will have no support to rest on. 

If you buy a mattress secondhand, then it will sag much faster than a new one, as it’s been used for longer.

This is why getting a cheap, used mattress is helpful in a pinch, but you’ll probably end up replacing it much sooner than you would have if you bought a brand-new mattress. 

If you’ve bought a new mattress but think it’s already sagging, check your bed frame first to see if there’s any damage there.

It could be that you are confusing the formation of body impressions in the mattress with a sagging mattress. This may easily be done, so check out how to spit body impressions further down. 

How To Tell If Your Mattress Is Sagging 

By measuring the dip, you will be able to work out whether the dents in your mattress are the result of normal body impressions or are the unmistakable indicators of a sagging mattress. 

When you’re measuring the dip/dent in your mattress, 2 inches deep is the magic number. If the dent is 2 inches or less deep, that means that the dents are simple body impressions, which is very good news. 

Anything more than 2 inches deep, and you sadly have a sagging mattress on your hands.

Body Impressions On A Mattress 

A quality mattress will mold to the specific contours of your body to provide the optimal level of comfort and support for your back. 

You’ve probably realized that you have a favorite sleeping position, one that you sleep in almost every night.


When this happens, the foam/springs in the mattress are constantly being compressed in the same area.

As the mattress conforms to the natural curves of your body, you could feel as though the surface of the bed has a slight indentation or “dip” in it.

Many people worry that this means that the mattress is already sagging, but this dip actually provides the very best support for your body as you sleep. 

Normal body imprints in a mattress are caused by the fibers and foam compressing and conforming to the shape of the sleeper’s body.

If your mattress has an indentation that is up to two inches deep, this does not indicate a manufacturing or sagging issue, but rather that you’ve left imprints. 

Body impressions have been shown in clinical studies to aid in the maintenance of proper spinal alignment and to give the necessary pressure reduction for a restful night’s sleep.

If the bed has an excellent body impression, it will be able to softly cradle your sleeping form and give you the highest possible level of comfort and stabilizing support.

Why Does My New Mattress Feel Firmer Than It Did In The Store? 

When you first get a brand-new bed, you could find that the mattress is a lot firmer than when you tested it out in the store. This isn’t an issue though!

A Sagging Mattresses Vs Mattress Body Impressions (1)

The upper layers are brand new and still require some “breaking in” time before they conform to your natural form, which is the reason for the increased hardness. 

When you buy a new mattress you have to break it in, just as you would with a new pair of shoes.

When you first put on a new pair of shoes, the soles will be rigid and straight, which will most likely cause you to experience some level of discomfort.

If you keep wearing the shoes, the soles will eventually mold to fit the natural curve and contour of your feet, which will result in a more comfortable fit.

In a similar vein, a quality mattress will mold itself to the specific contours of your body, providing you with a restful night’s sleep for years to come. 


Many people worry that their new mattress is sagging too soon, but the most likely reason is that they’re confusing body impressions with actual sagging. 

Sagging in a mattress usually only happens if the mattress is old and the internal components have broken down.

If you have a newer mattress and don’t think it should be sagging this soon, check the bed frame to see if there’s any damage under the mattress.

A lack of support under the mattress is another cause of sagging. 

In most cases though, it’s not sagging you’re seeing, but rather body impressions.

This is when the mattress contours to the shape of your body, meaning that it can support your body perfectly every night.

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