How to sleep in the heat, according to science
Posted by Claire Hewitt, on August 11, 2025.
Estimated reading time: 5 minute(s)
Another heatwave, another round of hot, sleepless nights. Trying to get a decent amount of shuteye during hot weather is hard. You won’t be the only one flinging off the covers, tossing and turning, and frantically shopping online for a bedroom fan right now. And if you happen to also be grappling with menopausal night sweats, you’re probably still awake at 2am wondering who set fire to your bed.
Hot temperatures and humidity during the day can leave us feeling weary and lethargic, so why do we find it so hard to nod off once our head hits the pillow? It’s all to do with the body struggling to kick-start the sleep process. Natural physiological changes involve the body’s core temperature dropping by 1-2°C, alongside a rise in melatonin levels, the hormone that promotes sleep. When the surrounding air temperature is much higher than normal, the body must work extra hard to cool down and deploys all kinds of overstimulating tactics to do so. It’s physically demanding on the body and mentally draining – not being able to drift off makes us even more anxious and stressed about having a bad night’s sleep, and the cycle continues…
Aside from sleeping in the fridge, what can we do to help us sleep better when we feel too hot? It’s all about keeping your body, bed and bedroom cool – the optimum temperature for your sleep environment (at any time of year) is approximately 18°C. Try some of these science-backed tips for maintaining the perfect temperature and establishing good sleep habits that will help you drift off long after the heatwave has gone.
Close curtains and blinds during the day
Keeping a bedroom protected from the heat of the sun during the day can ensure it doesn’t feel like an oven at night. Contrary to what you might think, it’s also a good idea to keep windows closed at this time too to block warm air from getting in. Once outside temperatures have cooled in the evening, you can open windows and doors to let the cooler air circulate. A study of sleep-improving tactics published in respected journal The Lancet even suggested pinning up a damp sheet against an open window at night, to create a misting effect.
Put bedding and nightwear in the fridge
It may be a bit inconvenient to remake your whole bed every evening, so you could place just a sheet, your nightwear or pillowcase into a plastic bag then into the fridge for a couple of hours before bedtime. Alternatively, transfer the fridge to your bed with a ‘reverse’ hot water bottle – fill it with cold water and pop it into the fridge (or even the freezer) before tucking it into bed.
If you choose only one piece of bedding to focus on, make it the pillow – keeping the head cool helps the whole body cool down. You could also place a cold flannel on your forehead for similar results (it will heat up though, so to avoid being woken up by a piece of hot, damp fabric in the night, remember to remove it before you nod off).
Choose breathable bedding and nightwear
Hot nights equal sweaty nights. It may be tempting to throw off all the covers and sleep naked, but you’re likely to wake up too cold when your core body temperature and the surrounding air temperature drop later in the night. Instead, ensure that nightclothes and bedding are made of light, breathable fabrics such as cotton and bamboo which are naturally sweat wicking, absorbing moisture from the skin which helps the body cool down. Our fuller-cup lounge bra Mia is perfect for sleeping in, not just because of its relaxed style but also its super soft organic cotton.
Stay hydrated throughout the day
As your body sweats to cool down at night, you’re at risk of dehydration which can impact your sleep-wake cycle and overall sleep duration. If you haven’t drunk enough liquid in the day, you could go to bed already dehydrated and suffer from other sleep-disrupting symptoms such as dizziness and muscle cramps. Not only does caffeine, sugar and alcohol disrupt sleep, they are also dehydrating so avoid these types of drinks late in the day and stick to around two litres of water.
Have a lukewarm bath or shower
It may be tempting to blast yourself with an ice-cold shower to cool down before bed – trendy ice baths and extra cold showers are believed to have far-reaching health benefits – but it may cause more problems when you’re trying to sleep in the heat. It’s actually better to exposure yourself to lukewarm (or slightly cool) water to avoid the overstimulating effects of ice-cold temperatures. Extreme cold provokes the body to drastically increase the core temperature to compensate, whereas lukewarm temperatures, lower than the surrounding air temperature, help the body cool down in a less stimulating way. If you don’t fancy a full-on bath or shower, dipping your feet or hands into cool water for a few minutes can also help.
Browse our dreamy sleep accessories for more ways to help you drift off including cotton-rich PJs, comfy lounge bras, and luxurious ethical silk sleep masks…
Cotton PJs
All of the collection pieces are made from high quality cotton fabrics, ensuring you can drift off to sleep blissfully or relax and lounge at your leisure
Mia Sleep Bra
Designed without any fastenings or components for extra comfort. Mia’s soft, wide straps and underband, plus its relaxed style makes it great option at night as a sleep bra
Eye Masks
These unique super-silky eucalyptus silk eye masks with an extra-smooth finish makes falling asleep so much easier. Drift off in style.
