Key Takeaways
- It may be comfortable, but memory foam has a reputation for sleeping hot.
- The cozy contouring that evenly distributes body weight also holds onto body heat, which can lead to overheating.
- Memory foam is a type of polyurethane, which means it’s synthetic. It doesn’t breathe or wick moisture, so it can also cause night sweats.
- If you can’t upgrade your entire mattress, an organic wool topper and organic cotton sheets create a breathable natural buffer between you and the heat-trapping memory foam.
- Hot sleepers do best on hybrid or natural mattresses made with latex and wool. Not only do they sleep cooler, they’re also better for your sleep (and the planet).
Memory foam mattresses sound great in theory, don’t they? The material responds to heat and pressure, so it molds to the shape of your body while you sleep. That level of close contouring helps keep you comfortable by evenly distributing your body weight, which alleviates stress on pressure points like your hips, shoulders and back. Plus, memory foam does an excellent job of absorbing movement, which means you won’t feel a restless bed partner moving around. But what many proud new owners of memory foam mattresses come to understand is that the material also excels at trapping heat. The same body heat that softens the material for that “hugged” sensation can also lead to serious overheating and night sweats, both of which are detrimental to a good night’s sleep. In the interest of a better night’s sleep, let us take a closer look at why your memory foam mattress is too hot at night—even if you upgraded to the model with a “cooling gel infusion.”
The Biggest Complaints About Memory Foam and Heat
Trapping heat is a common concern with memory foam. It’s right up there with the sensation of feeling trapped, which is how some people react to the slow sink inherent to the material. But what exactly is it about memory foam that makes it prone to holding onto body heat? For better or for worse, it’s simply the nature of the material.
Why Your Memory Foam Mattress Feels Hot
We’ve already covered how memory foam responds to heat and pressure, thanks to a dense structure of tightly packed cells. This is what allows the material to soften and mold to your body, with firmer support in areas of deeper compression (like your backside and hips) and softer support around the shoulders and legs. But because it’s heat responsive, it doesn’t just react to your body heat—it also holds onto it. That tight cell structure means body heat is absorbed and reflected, which means you’re cocooned in a bubble of your own heat. And unlike natural fibers, like wool or cotton, memory foam also reduces ventilation, which makes it really difficult for heat to escape.
Keep in mind, memory foam is a synthetic material—a specialized form of polyurethane, which is itself a special kind of plastic. Memory foam is mixed with additives like viscoelastic chemicals and blowing agents, for that signature slow-moving feel. In a bid to address the problem of overheating, some memory foam manufacturers may also incorporate gel particles or copper or graphite infusions. These materials offer some level of passive cooling by drawing heat away, but they don’t change the fact that memory foam just doesn’t breathe well or that it traps heat in the first place.
Why Excessive Sweating Might be Happening with a Memory Foam Mattress
Synthetic materials in general tend to trap heat more than their natural counterparts, and that’s particularly evident on a mattress. Whether it’s polyester, nylon or memory foam, these materials have that tight structure that limits airflow. It keeps body heat close to you for hours on end when you sleep, and that can lead to sweating as your body works to regulate its temperature. Keep in mind that our body temperature naturally fluctuates during sleep, and a mattress that holds onto heat can inhibit this process. Not only is it disruptive to your natural sleep rhythm, it means a pretty good likelihood of waking up in a puddle of your own sweat.
Synthetic materials are essentially plastic, so not only do they not breathe well, neither do they effectively absorb moisture. If you’re prone to overheating or you’re in a warm environment, that poses a problem. Memory foam doesn’t wick away sweat, which leaves you feeling damp and sticky. That’s not the case with natural fibers, which generally have impressive wicking abilities. Wool, for example, can absorb up to 30% of its weight in moisture without feeling damp or heavy.
Night sweats are pretty common—up to 41% of primary care patients report them—and there are a lot of medical conditions that can contribute to the issue. But if you can rule out menopause, mood disorders, hyperthyroidism, obesity and gastroesophageal reflux disease, the culprit could very well be your memory foam mattress!
Why You May Wake Up More on a Memory Foam Mattress
When you first lie down on a memory foam mattress, it takes a little time for the material to respond to your body. It’s just as slow to shift back to its original shape when you move (that’s the “memory” part of memory foam). If you’re a combination sleeper, rolling from one position to the next during the night, memory foam makes it pretty tricky to comfortably move around. That can make you feel stuck, which can be disruptive to a restful night’s sleep.
We cycle through four to six sleep stages in a typical night. Deep sleep and REM sleep are particularly important for physical recovery, mood and immune function. If you’re regularly waking up to readjust your sleeping position, there’s a good chance that you’re only getting lighter sleep and missing out on the complete deep sleep and REM cycles. That means you aren’t getting the restorative sleep you need to be healthy and functional.
How to Keep Cool on a Memory Foam Mattress
If you have a memory foam mattress, and it’s suddenly dawning on you that your restless nights could be because you simply get too hot, you aren’t doomed to bad sleep forever. Ideally, you might consider upgrading to a mattress made with natural materials, like wool and latex, which are much better suited to people who sleep warm. But if a new wool mattress isn’t in the budget today, here’s what else to try.
Cooling Your Sleeping Environment
Addressing the ambient temperature in your bedroom can help keep you more comfortable. Memory foam doesn’t promote airflow, so try running a ceiling or floor fan to circulate air. Running the air conditioner or cracking a window if the weather allows can help keep the bedroom temperature lower and more conducive to sleep as well.
Choosing the Right Bedding Materials
Your choice of bedding can be a major contributor to overheating, so don’t make a bad situation worse. Instead of springing for a brand new mattress, consider a wool mattress protector, pad or topper. We’ve already covered wool’s impressive wicking properties, but this breathable fiber also effectively regulates temperature to help you stay comfortable all night long. The wool layer acts like a buffer between you and the mattress, minimizing the sinking sensation to improve airflow around you. It makes your favorite memory foam mattress cooler and more breathable, without compromising on the contouring benefits.
Be mindful about your bed linens, too. Instead of synthetic sheets made from polyester or rayon, upgrade to breathable fibers, like organic cotton or organic cotton/linen blends. These materials are naturally lightweight and breathable, and they’re absorbent but quick to dry. It’s a great combination with an organic wool pad or topper for more comfortable nights, no matter what kind of mattress you have.
Sleeping Position and Memory Foam Heat Retention
Surprised to learn that your preferred sleeping position could also affect how much heat your memory foam mattress retains? It’s true! Certain positions mean more contact between your body and your mattress, which can contribute to more heat build-up.
- Side sleeping puts a lot of pressure on your hips and shoulders, so you sink in more deeply from your head all the way down your side to your feet. That means more trapped heat. A wool mattress topper and breathable sheets can help.
- Back sleeping distributes your body weight more evenly, so you actually sink into your mattress less than you would on your side. It allows for more airflow around your sides and limbs, which can make things a little cooler. Still, you may want to spring for the wool mattress topper and switch to lightweight sheets made with natural fibers.
- Stomach sleeping isn’t ideal on memory foam. It’s important to maintain a neutral spine in any sleep position, and stomach sleepers are more likely to experience sinking at the hips, which pulls the spine out of alignment. Plus, the position creates a lot of contact with the mattress, trapping heat around the chest, stomach and face.
When to Consider Replacing Your Mattress
While a wool mattress topper and breathable sheets is the best natural solution to a heat-trapping memory foam mattress, really hot sleepers may find it’s simply not enough—especially if the foam is really soft. If you’re not feeling rested in the mornings, regularly find yourself kicking off the blankets, or toss and turn at night trying to find a cooler, more comfortable spot, it might be time for a new mattress.
Hot sleepers generally do best with hybrid constructions, since the innerspring layer promotes airflow. Organic latex is temperature neutral, so it doesn’t trap heat the same way memory foam does. Plus, it offers comparable pressure relief and a more buoyant feel that some people really like. But it doesn’t have the signature sink of memory foam—with latex, you’re sleeping on top of the mattress, not sinking down into it. Organic mattresses are also worth considering. Since they’re made with naturally derived materials, they sleep cooler than mattresses made with synthetic materials. Plus, they have a number of additional perks. Organic wool mattresses, like those here at Woolroom, aren’t just more conducive to sleep. They’re also hypoallergenic, which is ideal for people with allergies, and sustainable, too. Our mattresses are made with traceable wool, and our Wool ID program makes it easy to see our ethical sourcing at every step—from the farm to our workshop to your bedroom!
The Bottom Line
There’s no question that memory foam sleeps hot. Even cooling infusions can’t fully combat the problem, and hot sleepers in particular should be fully aware of this issue. The good news is that you aren’t without options, even if you’re currently sleeping (and sweating) on memory foam. Cooling your bedroom with a fan, switching to breathable sheets and adding an organic wool topper to your mattress can make a big difference for cooler, more comfortable nights.
Frequently Asked Questions
Is memory foam hotter than a regular mattress?
Memory foam mattresses do sleep hotter than those made from natural materials, like wool and latex. Memory foam is a synthetic material with a dense structure. Not only does it trap heat, it doesn’t wick moisture, which is why many people find they get hot and sweaty on memory foam mattresses.
How to stop memory foam from making you sweat?
Try using an organic wool mattress topper and breathable sheets. Together, they create a natural buffer between you and the memory foam. Wool is naturally temperature regulating and moisture wicking, which can help combat heat retention in your mattress.
Which is hotter, latex or memory foam?
Memory foam retains more body heat than a natural latex mattress. Memory foam is a synthetic material that doesn’t breathe well or wick moisture. Its dense structure absorbs and reflects heat. Natural latex from the sap of rubber trees has an open-cell structure that promotes airflow, and the material is also temperature neutral.