Body Impressions in a Mattress: What's Normal?
If you browse mattress reviews, you're sure to come across comments about body impressions, those permanent indentations that tend to develop in the spot where sleepers lie each night. In fact, according to the folks at mattress review sites GoodBed and Tuck, body impressions are the number one complaint that consumers have about their mattresses.
And yet, it's hard to find good information about what, exactly, constitutes a "normal" body impression and when it's a sign of something more serious.
That's because some degree of body impression is to be expected with virtually every mattress on the market today, says Terry Cralle, RN, certified clinical sleep educator and Saatva sleep consultant. “It is unrealistic for a consumer to expect their mattress not to get body impressions," she says. "And by the way," she adds, "that's not necessarily a bad thing."
True, the rock-hard, flat mattresses popular a generation ago rarely showed impressions, “but Americans now prefer softer, more conforming beds," says Tuck's Keith Cushner. And that means pillow tops and comfort layers made of foams that, by their nature, are going to take on body impressions after you lie on them six, seven, or eight hours a night. “When you think about it, the same thing happens in time with every foam that holds our weight, like couch cushions, automobile seats, and sneaker insoles," Cushner observes.
Are body impressions in a mattress bad?
A slight body impression can actually make your bed more comfortable, Cralle says. That's because the impression fits you like a glove and is a sign the bed is breaking in and conforming to your shape. “A moderate impression can create a hugged, cradled sensation," notes GoodBed.com's Michael Magnuson. (Here's why quality mattresses need a breaking-in period.)
Too deep of an impression, though, can throw off spinal alignment and cause back pain. That's especially true if you sleep on your stomach, Magnuson says. The degree to which a person is bothered by body impressions may be related to how they sleep: Back sleepers tend to have less trouble with body impressions, says Cralle, and side sleepers may not notice them at all.
How much body impression is normal?
As a general rule, impressions of 1 inch or less are normal for an innerspring mattress, and 3/4 inch or less is to be expected with a foam mattress. Impressions deeper than that may be eligible for warranty coverage, depending on the mattress manufacturer. Pretty much every mattress type is likely to get impressions, says Magnuson, with one exception: high quality latex foam. Because of its natural resilience, latex "springs back" more than other materials.
In most cases, impressions form after two to four years sleeping on the mattress, though it can happen sooner.
What can you do about body impressions?
The way you sleep on and care for any mattress can moderate the development of body impressions (though not remove them once they form). Here are some techniques:
- Make sure your mattress is on a stable base, so it doesn't sag. (Here's what you need to know about bases and foundations.)
- Rotate your mattress regularly. If it's flippable, alternate between flipping and rotating. (A smart-phone reminder is probably the best way to ensure that you actually do it.)
- Try not to sleep in the exact same spot every night. Although you may move around in your sleep, starting in slightly different locations can help to reduce the amount of time your body is pressing on the same surface area.
- Use a mattress topper over a flat, firm mattress. A latex topper likely won't gain an impression. And whatever your topper is made of, you can replace it if it becomes uncomfortable.
- Meet your partner in the middle to snuggle and such. Your combined weight on this often-un-slept-on spot can help to avoid a hump from developing between you—especially if done with relative frequency.
- Finally, and perhaps most importantly, plan to replace your mattress every six to eight years. “These plusher, softer products are so much more comfortable than the stiff hard mattresses of a couple decades ago," says Cushner, “but they do not last as long."
Time for a New Mattress? See What Saatva Offers
For more helpful advice, consult our mattress buyer's guide for tips on finding the perfect bed.