Beat the Heat: How to Sleep When It's Hot

Posted by Dr Sophie Bostock - Sleep Expert on 16th Jun 2022

Beat the Heat: How to Sleep When It's Hot

Why is it so tough to sleep in the heat?

Our temperature naturally follows a 24 hour rhythm, peaking in the late afternoon and dipping to a low at around 4am. A rapid cooling of our core body temperature signals the onset of sleep. If we’re in an environment which is too warm, this natural cooling can’t take place. We struggle to fall asleep, and we are less likely to get into deep sleep. As we get older, we are more likely to struggle to sleep during extended periods of heat.

How can you sleep when it’s hot outside?

1. Can you keep air circulating at night?

Studies have found that even if you don’t have air conditioning, simply keeping air moving using a fan can help keep you cool, and improve sleep quality, even in the heat.

2. Can you keep your bedroom cool during the day?

If the hot sun shines through the windows during the day, the heat will build up. Use blackout blinds to keep the sunshine out during the day, and to keep your bedroom dark at night.

3. Could you switch to a cooler bedroom?

The sun sets in the west, so rooms with easterly facing windows are likely to be cooler in the evening. Warm air rises, so a ground floor room is likely to be cooler than an attic.

4. Could a separate bedcover help?

Experiment with a lower tog summer duvet (<5), a duvet cover alone, or just a sheet if you’re getting too hot during the night. Many couples find that having one single cover each (rather than sharing a double) is helpful for sleep during the summer, so that they share less body heat.

5. Could warming gently help you cool down before bed?

Though it sounds counterintuitive, a warm bath, shower or foot bath 1-2 hours before bed can help prepare the body for sleep. The warm water against the skin helps the blood vessels widen to increase blood flow to the extremities, resulting in a cooling of core body temperature. The bath wants to be warm - not hot enough to cause sweating.

6. Can you use cooling-friendly bedding and pyjamas?

Natural fabrics like cotton and silk are likely to wick moisture away from the skin more effectively than synthetic materials. Some mattresses are specially designed to improve their temperature regulating properties. Research has shown that using a specially designed cooling pillow can decrease the body’s sweat rate under humid conditions which we're prone to when sleeping in heat.

7. Is a cool drink within reach?

Staying well hydrated during the day will help your body to regulate temperature more effectively. Fill a thermos with cool water and leave it by your bed for a refreshing drink during the night.

authors profile
Dr Sophie Bostock
Sleep Expert
Sophie brings a wealth of expertise to the role having spent the last six years researching and championing the importance of sleep science in NHS and corporate settings. Sophie was responsible for improving access to the award-winning digital sleep improvement programme, Sleepio, as an NHS Innovation Accelerator Fellow. She has delivered hundreds of talks, including for TEDx and Talks@Google, and regularly features as a media sleep expert.
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