Tips to Keep You and Your Mattress Cool

From adjusting your bedding to tweaking your sleep routine, our Head of Sleep Science, Hannah Shore, and our Sleep Expert, James Wilson, also known as The Sleep Geek, have some tried and tested tips to help you get a good night’s sleep at the height of summer.

We all know the struggle – trying to drift off when it’s too warm. You toss, you turn, and you flip your pillow to the ‘cool side’ for the third time in as many minutes. We’ve all experienced it. But no matter how many times you try the other side of the pillow, you’ll never get to sleep if your body is too hot. If you’re wondering how to cool your mattress to help regulate your body temperature, you’re not alone.

To fall into deep sleep, our body temperature needs to drop a couple of degrees. While in winter that's usually easy, when we’re experiencing a heatwave, it’s easier said than done. If you’re looking for ways to cool down your mattress and create a more comfortable sleep environment, there are several simple changes you can try.

1. Swap out your duvet for a cooler sleep

Our homes are built to keep heat in, which is great in winter, but not so great in summer. If you’re still sleeping under a thick 13.5 tog duvet in July, it’s time to switch. A lighter 4.5 tog option allows your body to breathe and prevents overheating.

If you tend to overheat year-round, consider using a lower tog duvet even in winter. You can always layer a blanket on top for extra warmth on colder nights. Quality sleep is all about finding what works for you.

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2. Choose the right bedding

Your bedding, pillows, and mattress topper all contribute to temperature regulation¹. The golden rule? Stay away from materials that trap moisture. Opt for breathable fabrics like bamboo or polyester, which wick away sweat and dry quickly. And whatever you do, James says don’t fall for the internet’s strangest sleep hack – putting your bedding in the freezer!

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3. Choose a cooler mattress or pillow

If you often wake up feeling too hot, it might be time to ditch foam-based mattresses and pillows. Foam retains heat and moisture, making you feel even warmer.

Instead, opt for natural fibres like wool, silk, or bamboo, which wick moisture away and help regulate temperature. Surprisingly, polyester can also be a great option, as it moves heat and moisture away rather than trapping it.

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4. Keep your bedroom cool

Lowering your bedroom temperature is one of the easiest ways to improve sleep quality. But if you’re still overheating, knowing how to keep your mattress cool at night can be just as important. While there’s no universal ‘perfect’ sleeping temperature, keeping your bedroom slightly cooler than the rest of your home helps you fall asleep faster and stay asleep longer.

Here are some quick ways to keep your room and mattress cool:

• Turn down the radiator (or turn it off altogether in summer)
• Use oscillating fans to move air around the room, and place a bowl of ice in front of the fan to create a DIY air-con effect
• Keep your curtains or blinds closed during the day to stop your room from heating up in the sun
• Keep your windows closed during a hot day to keep warm air out, but open them at night as the temperature dips and the air moves

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6. Wear the right pyjamas

Your sleepwear can make or break a cool night’s sleep. Stick to light, loose-fitting clothes made from breathable materials like bamboo or moisture-wicking polyester.

Other quick fixes can include:

• Tying long hair back to keep your neck cool
• Ditching thick socks, as your feet help regulate body temperature
• Consider sleeping in as little clothing as possible if you're really struggling

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7. Adjust your sleep routine

Some pre-bedtime habits can raise your body temperature without you realizing it, making it harder to fall asleep. Ideally, you should start winding down before bed by relaxing both your mind and body. This includes calming racing thoughts and allowing yourself to feel tired naturally.

If this is something you struggle with, try these simple adjustments:

• Avoid big meals late at night - Digestion increases core temperature.
• Skip hot showers and baths close to bedtime - While relaxing, they can cause a temporary body temperature spike. Opt for a lukewarm shower instead².
• Time your workouts carefully - Late-night exercise raises body temperature, making sleep more difficult.

Nighttime dos and don'ts for a cool night’s sleep

Your core temperature can also make your mattress warmer, so it's useful to lower your body temperature as much as possible before bed.

Here are some quick tips:

Dos	Don’ts
Apply a cool compress to pulse points for quick relief	Drink alcohol – it dehydrates you, which can make you feel warmer
Drink cool water before bed to stay hydrated	Consumer caffeine – it gives you more of a 'buzz', which can make you feel stuffy3
Exercise in the morning to avoid overheating at night4	Wear heavy or tight-fitting clothing – it can make you sweat more5

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Getting a good night’s sleep in hot weather isn’t impossible – it just takes a few tweaks. From learning how to cool down your mattress to adjusting your sleep environment, small changes can make a big difference.

For more sleep advice, visit our sleep journal

For more tips, check out James’ guide on how to fall asleep and stay asleep during hot weather below:

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References:

1. Zaki, S.A. et al. (2021) Effectiveness of a Cool Bed Linen for Thermal Comfort and Sleep Quality in Air-Conditioned Bedroom under Hot-Humid Climate, MDPI. Available at: https://www.mdpi.com/2071-1050/13/16/9099.
2. Haghayegh, S. et al. (2019) Before-bedtime passive body heating by warm shower or bath to improve sleep: A systematic review and meta-analysis, PubMed National Library of Medicine. Available at: https://pubmed.ncbi.nlm.nih.gov/31102877/.
3. McHill, A.W., Smith, B.J. and Wright, K.P. (2014) Effects of Caffeine on Skin and Core Temperatures, Alertness, and Recovery Sleep During Circadian Misalignment, Sage Journals. Available at: https://journals.sagepub.com/doi/10.1177/0748730414523078.
4. Stutz, J., Eiholzer, R. and Spengler, C.M. (2019) Effects of Evening Exercise on Sleep in Healthy Participants: A Systematic Review and Meta-Analysis, PubMed National Library of Medicine. Available at: https://pubmed.ncbi.nlm.nih.gov/30374942/.
5. Li, X., Halaki, M. and Chow, C.M. (2024) How do sleepwear and bedding fibre types affect sleep quality: A systematic review, Wiley Online Library. Available at: https://onlinelibrary.wiley.com/doi/10.1111/jsr.14217#jsr14217-bib-0034.