6 heatwave sleeping mistakes - and what to do instead

The ongoing heatwave is making it hard to sleep. Here's how you could be making it worse, and what to keep cool.

An electric fan next to a modern queen bed with a sunset in the background
(Image credit: Getty Images)

Many of us love the sunny weather. But when the sun goes down and it's time for bed, it can be nearly impossible to sleep. Trying to rest when it’s hot or humid can be a challenge and have huge knock on effect in the rest of your life.

That's why it's such a good idea to make sure that your evening routine and sleep environment is conducive to getting a restful night’s sleep, and it's even more crucial when it's hot. 

However, there are some small but important mistakes that may be making it harder for you to sleep in hot weather. 

I spoke with Dr Lindsay Browning, psychologist and sleep expert, to hear her tips on how to make sure you sleep well, even when it's hot. Even if you've got one of the best mattresses, you might not be getting proper sleep. Let’s look at the mistakes you might be making and what you should be doing instead. 

6 hot weather sleeping mistakes

1. Opening the windows during the day

Double bed in pale grey bedroom with wooden floor, cream and white bedding and white curtains dressing floor to ceiling windows. A renovated four storey London townhouse, home of Louise Bradley, interior designer.

(Image credit: Future)

When it’s hot our natural instinct is to open all the windows in our house to try and get fresh air blowing through. The trouble is that in hot weather there’s likely to be very little airflow. 'Generally, when it is really hot outside it is a good idea to keep windows closed during the daytime, as you don’t want the hot external air to come into the house warming it up', explains Dr Browning.

Instead, open your windows at night. 'After the sun goes down, the outside air will start to cool down', says Dr Browning. 'At this point, it is a great idea to open the windows to let in a breeze of cool external air into the bedroom, helping cool the room and to provide needed air circulation. If you live by a noisy street this may not be advantageous as the noise may make it hard to sleep, but as long as you don’t live next door to a barking dog or a train station, it’s worth a try.'

A headshot of sleep expert Lindsay Browning
Dr Lindsay Browning

Obtaining a doctorate from the University of Oxford, Dr Lindsay Browning is a Chartered Psychologist and Associate Fellow of the British Psychological Society. She is also a member of the British Sleep Society and has published several publications about sleep and game theory. Dr Browning is passionate in helping people of all ages to sleep well.  

2. Exercising too close to bedtime

This won't be a problem for everyone, particularly those of us adverse to exercise in the first place, but it’s a bad idea to exercise too close to your bedtime. People tend to think that exercising in the cooler evening hours is a good idea, but Dr Browning explains that this is an error. 'Engaging in vigorous exercise too close to bedtime can impact your ability to cool down and potentially disrupt your sleep. When you exercise vigorously, your body temperature rises, and it can take some time for it to return to normal levels. This rise in body temperature can interfere with the natural cooling process that occurs during sleep and make it more challenging for you to fall asleep or maintain a restful sleep.'

So, if you do want to exercise, how should you go about it? Dr Browning explains, 'Ideally, it's best to allow a sufficient cool-down period after vigorous exercise before going to bed. This will give your body enough time to lower its temperature and return to a more relaxed state. The specific duration needed for a cool-down period can vary from person to person, but a general guideline is to avoid exercising vigorously within two to three hours before bedtime.'

3. Eating too late in the evening

A late-night meal outdoors - steak and romano beans with a glass of white wine

(Image credit: Getty Images)

When the evenings are lighter, it makes sense to eat a little later. But if you’re still going to bed at your regular time, as you should be to promote a good sleeping pattern, you run the risk of not having enough time to digest your food before you go to sleep. This can lead to indigestion and a restless night.

In hot weather it’s a good idea to avoid foods and drinks that raise your body temperature, such as spicy or acidic food. Fermented foods, which contain the amino acid tyramine, have been shown to increase brain activity and make it harder to fall asleep. Unfortunately for those of us who like a glass of wine in the evening, late-night alcohol is also a no-no as it reduces the quality of your sleep.

The most important thing you can do is to ensure you remain hydrated throughout the day with water. And make sure you have water with you overnight. 'Having a cool glass of water next to your bed at night can be a convenient and helpful way to ensure you can hydrate easily especially if you tend to wake up feeling thirsty or dehydrated,' explains Dr Browning. 

4. Polyester materials

How often do you actually look at what your nightwear or bedding is made from? Polyester is an incredibly common material, but it’s not the best if you’re trying to keep cool. Natural fibres are your friend, as Dr Browning explains. 'It's important that if you want to stay cool you should stick to natural fibres such as cotton. Cotton pyjamas are great for the heat because they can help to wick away moisture like sweat. This helps lower your temperature because the vapour is free to transfer through the fibre, lowering the humidity between the fabric and the body, which provides you with a cool feeling.' 

Try replacing polyester sleepwear with luxurious cotton pyjamas like these at Net-a-Porter, or a more inexpensive option in this 100% cotton plaid pyjama set at Target. Polyester fabrics absorb sweat,  trapping you in a gross cycle of getting sweaty, your clothes being sweaty, which makes you hot and sweaty again, and so the cycle continues. There's no such danger with cotton. 

Dr Browning adds that this isn't just for sleepwear, but for your sheets, too. 'If you are someone that needs to sleep under the covers at night, instead of your duvet (no matter how low the tog) opt for a straight cotton bedsheet or quilt cotton cover instead. If there are two of you, have one each. This will ensure moisture wicks away from each individual and bed-sharers don’t end up sticking to each other. If you can bear it, sleep with your feet outside of the covers as well. We lose heat from our head and feet, by covering them you are trapping the heat. Set those toes free and feel cooler as a result.'

5. Not washing bed sheets frequently enough

Bedroom with green antique bookcase and pink bed sheets

(Image credit: Tamsin Johnson / Jonathan Bond)

'Washing your bed sheets more frequently during hot weather is a good practice to maintain cleanliness and hygiene', says Dr Browning. 'When the weather is hot, you're more likely to sweat during sleep, and that sweat can be absorbed by your bedclothes, bedding, and even your mattress over time. Sweat not only carries moisture but also contains oils, dead skin cells, and bacteria. Allowing these substances to accumulate can create an environment that is less fresh and potentially contribute to unpleasant odours, allergens, or even the growth of mould or mildew'. 

6. The wrong mattress

One of the big sleeping mistakes that many of us make is sleeping on the wrong mattress or under the wrong bedding. For example, memory foam mattresses can sleep extremely hot, with the ‘hug’ of the foam trapping heat and making us feel uncomfortable at night. If you sleep hot at night you could consider investing in one of the best cooling mattresses on the market, but these don’t come cheap and, unless your mattress actively needs replacing, could be seen as an extravagance. For a more reasonably priced way to keep cool at night, consider one of the best cooling mattress toppers, or best cooling sheets.

Sleeping in hot weather FAQs

How do I sleep in hot weather without a fan or AC?

If you don't have an electric fan, ceiling fan, or AC, prevention is your best bet. Keep the air in your house as cold as possible in the morning by keeping your windows shut and drawing your blinds or curtains. It sounds counterintuitive, but by doing this you keep the sun and hot air out of the house, making it cooler than the outside air. A few hours after the sun sets, open your windows for fresh, cool air. 

Should I sleep downstairs in a heatwave?

You don't have to, but it helps. Heat rises, so it can be cooler to sleep downstairs rather than your bedroom. However, if you haven't got a bed downstairs, and most don't, it could end up feeling hotter. Sleeping on a leather sofa, for example, will make you feel much more uncomfortable than sleeping in cool cotton sheets. 

These tips are all useful, but it also helps to have a good fan or air purifier to keep the air in your home cool and clean, as this can also make it feel much colder. 

Jo Plumridge

Jo Plumridge is a freelance writer and photographer with over 20 years of experience writing for a variety of magazines, websites and books. She writes, perhaps unsurprisingly, about photography, but also on all things interior design and sleep-related, alongside reviews of home and tech products. Jo loves exploring the latest design trends, although she’s yet to find a carpet that doesn’t show up the cat hair from the cats she and her husband foster.