What Happens if You Sleep on a Memory Foam Mattress Before 24 Hours?

You’ve set up your new memory foam mattress, but the mattress company suggests you wait at least 24 hours before you sleep on it. Do you sleep on your old mattress or even the floor the first night? Would sleeping on your new bed within a day ruin it?

There’s a reason companies ask you to wait before you sleep on an unboxed mattress, and it’s not that you’ll wreck the mattress—it takes years of sleeping on a good mattress to wear it down. Instead, the rule exists to make sure your first night on your new mattress is as comfortable as it can be.

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What is a Bed in a Box Mattress?

Bed in a box mattresses are rolled up and compressed by a machine, and then placed in a box for easy delivery—a boxed up mattress takes up less space in a delivery vehicle than one that’s expanded and laid flat. Because it’s been compressed, the mattress needs time to expand once it’s unboxed.

Foam beds (memory foam, latex, polyurethane) are often sold as bed in a box mattresses since the foam layers compress well. While there are hybrid and even innerspring bed in a box mattresses, these types are less common as mattress coils do not compress as well as foam.

No matter what mattress size you buy, whether it is as small as a twin or as large as a king, the manufacturers can compress and roll it up inside a box.

Why a Memory Foam Mattress?

A memory foam mattress is one of the best mattresses to relieve pressure points. The material responds to weight and heat, which allows it to conform to your body. No part of you is unsupported when you sleep on a memory foam mattress, leaving you waking up refreshed and pain-free.

Why Wait 24 Hours?

The truth is, it shouldn’t damage a quality mattress if you go against the 24-hour rule and sleep on it a couple of hours after unboxing. The rule mostly exists to make sure you get a good night’s sleep on your mattress, as the bed is hardly at its most comfortable when it’s still expanding. Waiting 24 hours also gives time for that new mattress smell to dissipate.

Why Does My New Mattress Smell?

Many new memory foam mattresses have a smell when first opened. The smell is produced when volatile organic compounds (VOCs) in the mattress break down at room temperature in a process known as off-gassing. The smell typically vanishes within three to seven days.

If the smell bothers you the first night, try encasing your mattress in a waterproof protector. The mattress protector should quarantine the odor, leaving you free to get a good night’s rest. Plus, the protector will keep your mattress stain-free.

You can reduce the risk of off-gassing by buying a memory foam bed certified by CertiPUR-US®. CertiPUR-US® ensures foams contain low amounts of VOCs for minimal off-gassing.

Can I Speed Up the Expansion Process?

If you want to break in your mattress quicker, then you need to do more than just lie down on it at night. The foam responds to heat and body weight, so stretch out, roll around, and walk across your mattress during the day. Raising the room temperature can also soften the foam.

What If My Mattress Doesn’t Expand?

Some new memory foam mattresses take longer to expand than others—it all depends on your foam’s quality. However, if your mattress has not finished expanding after a week, you most likely have a defective mattress. If you have a defective mattress, reach out to the company’s customer service for a replacement or a refund.

What if the Mattress isn’t Comfortable?

You waited 24 hours, and your mattress still isn’t as comfortable as you’d like. That’s natural, as many sleepers take at least a few days to adjust to a new bed. When you slept on your old mattress, your body adapted even as the mattress wore out, leaving you with bad sleeping postures that a new, improved mattress has to correct.

If you find after a month, you’re still not comfortable on your new mattress, you can try returning it within the sleep trial. If you can’t return your mattress, you can change its feel with a mattress topper. Toppers add a couple of extra inches of foam to give your bed a firmer or softer feel.

Does My Memory Foam Mattress Need A Box Spring?

We strongly recommend you do not keep your memory foam mattress on a box spring. The inner coils of a box spring are not close enough together to support a memory foam mattress, which can cause premature sagging. Typically, a memory foam mattress’s warranty is void if it’s kept on a box spring.

The best foundation for a memory foam mattress is a solid or slatted platform. If slatted, the slats should be no more than 2.75 inches apart and at least 0.5 inches thick.

Frequently Asked Questions

What is the difference between memory foam and gel memory foam?

Gel foam is like memory foam in many ways—both offer excellent pressure relief. The main difference is that manufacturers infuse gel foam with cooling gels since traditional memory foam retains body heat.

Is memory foam toxic?

Memory foam mattresses are safe to sleep on—the concerns about memory foam’s toxicities mostly involve chemicals that workers might be exposed to during production. If you’re concerned about buying a nontoxic mattress, look for a certification such as CertiPUR-US® or GREENGUARD Gold.

Can memory foam cause back problems?

A memory foam mattress is one of the best mattresses for back pain since it conforms well to the curves of your body. However, a mattress can cause back issues if you don’t choose a firmness that matches your sleeping position. Side sleepers need a soft to medium mattress, while back and stomach sleepers need a medium-firm to firm mattress.

Did We Help?

The worst that should happen if you sleep on a memory foam mattress within 24 hours is that you get as much quality sleep as you will once you’ve slept on the mattress for a week. A new mattress needs about a day to finish expanding while you need up to a month to adjust to your new mattress. As time passes, your mattress should feel more comfortable, and you’ll find yourself sleeping better than you did before.

This article is for informational purposes and should not replace advice from your doctor or other medical professional.

Sarah Anderson, Certified Sleep Science Coach Sarah Anderson

Sarah Anderson is a sleep, health, and wellness writer and product reviewer. She has written articles on changing and improving your sleep schedule, choosing the right mattress for chronic pain conditions, and finding the best pillow for you. Sarah Anderson has her Bachelor of Arts degree from Arizona State University in Journalism and Mass Communications. Prior to working for Zoma, she wrote for a variety of news publications. Sarah's work has been featured on Bustle, PureWow, and other publications.

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  1. Thank you for this information. It’s truly helpful. I unboxed my mattress yesterday and was too excited to wait because I had been sleeping on a futon. Your article helped put my mind at ease. Again, thank you.

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