Being too hot when you sleep is not only uncomfortable, it can actually interfere with your natural sleep cycle. In fact, one study found that being too warm when you sleep can disrupt stages three and four of sleep—the deepest and most restorative phases, during which body tissues repair themselves—as well as REM sleep, when memories are consolidated.
To mitigate the tendency of certain types of mattresses to trap heat, manufacturers have started to add cooling technology to their bedding products. One of the newest options you’ll find is graphite.
Here, learn about how graphite works and how it can help you achieve a cooler night’s sleep.
What is graphite?
Graphite is a naturally occurring form of crystalline carbon that’s found in metamorphic and igneous rocks. It is very soft, as well as resistant to heat; both of these properties give it a wide range of uses in manufacturing. Graphite has been used for years to pull heat away from expensive components in computers and phones, for example. The secret to graphite’s success is its small spherical “pores,” which allow it to absorb heat better than other elements often used for cooling.
Where is graphite popping up in bedding these days?
For the most part, cooling substances such as graphite are used in memory foam mattresses since innerspring and latex mattresses have a more open structure that allows for better airflow.
Memory foam mattresses are made from viscoelastic foam, a type of high-density polyurethane foam. (Greener versions use plant-based ingredients like soybean oil in place of some of the petroleum derivatives.) Memory foam’s distinguishing feature is that it softens in response to heat and pressure, which makes it a favorite among many sleepers—except for the fact that it holds onto heat. That’s where cooling elements come in.
To make graphite memory foam, graphite is either mixed into the foam itself or applied as a thin, separate layer on the top of the mattress. The weight of the sleeper sinking into the foam forces the graphite particles closer together, allowing them to conduct heat through the foam and dissipate it quickly.
Related: Why some mattresses “sleep hot” (and what to do about it)
Where else can you find graphite?
In addition to mattresses, memory foam pillows and mattress toppers now come in graphite-infused versions. Graphite in a memory foam pillow specifically will draw heat away from your head and neck, one of the warmest parts of the body.
What are some other popular cooling materials besides graphite?
Graphite-infused products are a great way to stay cool, but not the only way. Other products to help you chill while you sleep include:
Gel-infused memory foam
Similar to graphite-infused mattresses, toppers, and pillows are those infused with polymer gels, which also work by effectively soaking up the thermal energy from your body and dispersing it throughout the surface of the mattress. Some gels are infused with copper, another element with cooling properties.
Cotton is naturally porous, hence highly breathable, which is why it feels cool against your skin and is used in bedding products and pajamas. Some synthetic fabrics have similar cooling capabilities, but many are made using chemicals or chemical processes.
Bamboo is one of the most breathable and lightweight fabrics. As with cotton varieties, you can find sheets and pajamas made of this fabric. Bamboo is also eco-friendly.
This synthetic material absorbs sweat—a quality that is highly appreciated if you’re experiencing night sweats, one of the common complaints among menopausal women (or if you’re just sweaty in general).
Electric cooling pads
Electric cooling pads go on top of the mattress like a regular topper but are slightly thinner than regular toppers. The downside is that you have to plug them in, which some people find off-putting.
Finally, there are the obvious, old-school options, such as fans, cranking up the A/C, and sleeping in the buff.
The right sheets can also prevent you from overheating while you snooze. Here are the best sheets to keep you cool.