Illustration with a person in bed under a blue blanket with a bedside lamp and digital alarm clock on a bedside table

How to sleep in the heat: here’s what actually works, according to science

25 July 2026

It's 1am, you've kicked off the duvet, flipped your pillow four times, and you're still wide awake. If the current heatwave is impacting your sleep quality, you're not alone: heat is one of the most disruptive things for sleep, and there's a physiological reason for it.

In my clinic, poor sleep is one of the issues that comes up time after time - and never more so than during a UK heatwave. Most of our homes simply weren't built with cooling in mind: solid brick, small windows, loft bedrooms that trap the day's heat well into the night. So, when temperatures climb, sleep is often the first thing to suffer.

If you're wondering how to sleep in heat like this, here's what's actually going on. In this article, we'll look at why heat disrupts sleep at a physiological level, practical ways to cool down your bedroom and body without air conditioning, how to use a fan properly, a quick-reference checklist for your room setup, and what to do when the heat meets an already restless mind.

Why heat disrupts your sleep (not just comfort)

Struggling to sleep in the heat isn't simply a matter of feeling too warm to get comfortable - it interferes with one of the body's core signals for falling asleep in the first place.

To fall asleep, your core body temperature needs to drop by around half a degree to a full degree Celsius. This dip is part of your circadian rhythm, and it tells your brain and body that it's time to wind down (1). Your body manages this mostly through vasodilation - widening the blood vessels in your hands, feet and face so heat can escape and your core can cool. It's why your hands and feet often feel warm just before you drift off.

In hot, humid conditions, this process struggles. If the air around you is warm, there's less of a temperature gradient for your body to release heat into, so that internal cooling signal is delayed or blunted altogether (2). The result: it takes longer to fall asleep, you wake more often, and you spend less time in deep, restorative sleep - even if you technically get the same number of hours in bed.

This is also where the well-known "best temperature for sleep" guidance comes from. Most sleep research points to a bedroom temperature in the high teens (around 16-19°C) as optimal for sleep onset and quality (3). In other words, the best temperature for sleeping sits well below what most of us are used to in a UK summer nowadays. Anything meaningfully above that, and your body is working against itself trying to wind down.

Illustration of hand holding a glass of water at a bedside table next to a digital alarm clock showing 04:15, pill bottles and a lamp

How to sleep in hot weather without AC

Most UK homes don't have air conditioning, so the goal isn't to chase an unreachable "cold room" - it's to work with what you've got. A few adjustments can really help:

Choose breathable fabrics: Natural fibres like cotton, linen and bamboo allow air to circulate and wick moisture away from the skin far better than synthetic bedding or nightwear. If you can, swap your usual duvet for a lower tog, or sleep under just a sheet.
Time your windows and blinds strategically: Keep blinds or curtains closed during the day to block direct sun from heating the room, then open windows in the early evening and again first thing in the morning to let cooler air in and trapped heat out.
Take a cool (not ice-cold) shower before bed: This helps lower your skin temperature quickly, which supports that core temperature drop we mentioned above. A shower that's too cold can actually cause your body to react by retaining heat, so aim for lukewarm to cool rather than icy.
Be mindful of hydration timing: Staying hydrated through the day supports your body's ability to regulate temperature, but try to taper fluids slightly in the hour before bed to avoid disrupting sleep with night-time wakeups.
Cool your pulse points: Wrists, neck, temples and the backs of your knees are all areas where blood vessels sit close to the skin. A damp flannel or cool pack on these areas can bring quick, noticeable relief.
Keep a short wind-down routine: Even in the heat, a consistent, calming pre-bed routine helps cue your body that sleep is coming.
Dim the lights early: Bright light in the evening delays the release of melatonin, your sleep hormone - something that's already working against you when your body is also fighting the heat.
Try a frozen hot water bottle: It sounds counterintuitive, but it works well: fill a hot water bottle roughly two-thirds full with ice cubes and cold water (never fill it completely, so there's room for the ice to expand safely) and pop it under your pillow, tucked under your armpits, or resting on your lower belly. These are all areas where cooling can help bring your core temperature down faster.

Woman sleeping in bed with warm sunlight streaming across

Fan on bed? The right way to use airflow

A fan doesn't cool the air, it moves it. That distinction matters for how you use one effectively.

Don't just point it at your face: Airflow works by helping sweat evaporate off your skin, which is what cools you. A fan aimed only at your face does little for the rest of your body and can also dry out your eyes and throat overnight.
Position it to create cross-ventilation: If you have two windows, place a fan facing outward in one to push warm air out, and let cooler air draw in through the other. If you only have one window, position the fan so it pulls air in from outside rather than simply recirculating warm indoor air.
Try the ice-pan trick: Place a shallow bowl or roasting tin of ice (or a few frozen water bottles) in front of a standing fan. As the ice melts, the fan blows the cooled, slightly damp air across the room - a simple way to mimic a bit of air conditioning.
Angle it low, not high: Cool air naturally sinks, so positioning a fan lower in the room, angled slightly upward across the bed, tends to circulate cooler air more effectively than one perched high up.

Keeping cool at night: room setup checklist

A quick-reference checklist for setting your room up before you even get into bed:

Blackout blinds or curtains: closed during the day to stop the room absorbing heat.
Sleep on the lowest floor available: heat rises, so a ground floor room (even temporarily) is usually cooler than an upstairs or loft bedroom.
Dehumidifier if you have one: lower humidity helps sweat evaporate more efficiently, making the same temperature feel cooler.
Freeze your bedding or pillowcase: popping a pillowcase or thin sheet in a bag in the freezer for 10-15 minutes before bed gives you a genuinely cooling starting point.
Chill the bed in advance: fill a hot water bottle two-thirds full with ice cubes and cold water (leaving room for expansion) and place it in the bed 15-30 minutes before you get in, to cool the sheets ahead of time.

Close-up of beige and cream textured pillows and bedding

When heat meets a restless mind

Heat is a physical stressor - but it rarely arrives alone. Add in the ordinary background noise of a busy mind, and a hot night can quickly tip into a genuinely difficult one. When your body is already working overtime to cool down, an activated nervous system makes it even harder to switch off.

This is where an evening wind-down routine earns its place - not as an extra chore, but as a signal to your nervous system that it's safe to relax, even while your body's still doing the work of cooling itself down. Dimming the lights, a cool shower, and a consistent bedtime are a good foundation, but some people find it helpful to add a calming ritual on top - a warm (not hot) herbal tea, some gentle stretching, or a moment of quiet before lights out.

Some also look to CBD as part of this wind-down routine. CBD (cannabidiol) may help to support relaxation, reduce stress and general comfort in the run-up to sleep. Some people specifically look to CBD for sleep as preliminary research suggests CBD can interact with the body's endocannabinoid system, which plays a role in regulating mood, stress response and pain perception (4). It isn't a sedative and it won't cool your room down - but as part of a broader evening routine, some people find it supports a sense of calm that makes it easier to settle, heat or no heat. The ECS doesn't work in isolation, either. Nutrients like magnesium glycinate and B vitamins, and botanicals such as L-theanine, passionflower and Montmorency cherry, are often looked to for their role in supporting the body's natural wind-down processes alongside compounds like CBD - each interacting with the body's stress and sleep signalling in slightly different ways. Provacan's Sleep supplements range has been formulated with this evening routine in mind, alongside good sleep hygiene rather than instead of it.

As always, CBD and supplements are not a cure for poor sleep and shouldn't replace good sleep hygiene or medical advice where needed - they sit alongside these things, not in place of them.

Full range of Provacan CBD oils: 3%, 6%, 12%and 24% amidst bedsheets

Final thoughts: sleep through the heat, not despite it

Warm nights are, unfortunately, part and parcel of a UK summer - and heatwaves are only becoming more frequent. But a hot bedroom doesn't have to mean a wrecked night's sleep. Understanding why heat disrupts your body's natural cooling signal is the first step; adjusting your bedding, airflow, room setup and evening routine accordingly is the rest.

If you're looking for extra support winding down on hot, restless nights, explore Provacan's Sleep supplements range as part of your evening routine.

Sources

Harding, E.C., Franks, N.P. and Wisden, W., 2019. The Temperature Dependence of Sleep. *Frontiers in Neuroscience*, 13, p.336. https://www.frontiersin.org/articles/10.3389/fnins.2019.00336
Kräuchi, K., 2007. The thermophysiological cascade leading to sleep initiation in relation to phase of entrainment. *Sleep Medicine Reviews*, 11(6), pp.439-451. https://pubmed.ncbi.nlm.nih.gov/17652008/
The Sleep Charity, 2023. The Ideal Temperature for Sleep. https://thesleepcharity.org.uk/
NHS, 2023. Cannabis-based products for medicinal use. https://www.nhs.uk/conditions/medical-cannabis/

Back to blog

Frequently Asked Questions on how to sleep in the heat

How do you sleep in heat?

The key is helping your body do what it naturally wants to do: drop its core temperature. Focus on breathable bedding, timing your windows and blinds to keep the day's heat out, a cool (not icy) shower before bed, and cooling pulse points like your wrists and neck. Small, consistent changes make more difference than any single fix.

How do you sleep in hot weather without AC?

Most UK homes don't have AC, so the goal is to work with what you've got: breathable fabrics, strategic use of blinds and windows, a cool pre-bed shower, hydration timing, and cooling pulse points. A frozen hot water bottle under the pillow or against the lower belly can also help bring your core temperature down faster.

What is the best temperature for sleep?

Most sleep research points to a bedroom temperature in the high teens, around 16-19°C, as optimal for sleep onset and quality. Above that range, your body has to work harder to trigger the natural temperature drop that helps you fall asleep.

What is the best temperature for sleeping if my room runs hot?

Even if you can't get your room down to 16-19°C, every degree closer helps. Prioritise cross-ventilation, blackout blinds during the day, and cooling your body directly (via a shower or pulse points) rather than just the air around you.

Why can't I sleep when it's hot, even if I'm tired?

To fall asleep, your core body temperature needs to drop by around half a degree to a full degree Celsius as part of your circadian rhythm. In warm, humid conditions, there's less of a temperature gradient for your body to release heat into, so that internal cooling signal gets delayed - meaning you can feel exhausted but still struggle to drift off.

Fan on bed at night - should I point it directly at my face when it's hot?

Not ideally. A fan cools you by helping sweat evaporate off your skin, not by cooling the air itself, so aiming it only at your face does little for the rest of your body and can dry out your eyes and throat overnight. Positioning it for cross-ventilation, or angled low across the bed, tends to work better.

How can I make a fan colder using ice?

Place a shallow bowl or roasting tin of ice, or a few frozen water bottles, in front of a standing fan. As the ice melts, the fan blows the cooled, slightly damp air across the room - a simple way to mimic a little air conditioning without one.

What's the best way of keeping cool at night without AC?

Closed blackout blinds during the day, sleeping on the lowest available floor, using a dehumidifier if you have one, and freezing your pillowcase or bedding for 10-15 minutes before bed all help. A hot water bottle filled two-thirds with ice and cold water, placed in the bed 15-30 minutes before you get in, is another effective way of chilling the sheets in advance.

Does a hot water bottle filled with ice actually help you sleep?

Yes - filling a hot water bottle roughly two-thirds full with ice cubes and cold water (leaving room for the ice to expand safely) and placing it under your pillow, under your armpits, or on your lower belly can help lower your core temperature in areas where blood vessels sit close to the skin, supporting the natural cooling process your body needs to fall asleep.

Can CBD help you sleep in hot weather?

CBD isn't a sedative and won't cool your room down, but it interacts with the body's endocannabinoid system: the network that regulates sleep, mood stress response and pain perception. That's why some people include it as part of a broader evening wind-down routine, alongside good sleep hygiene, to support a sense of calm that makes it easier to settle - heat or no heat.