‘Many people think it’s going to be better to sleep naked in summer, but in fact wearing natural fibres like linen, bamboo, cotton or silk are more beneficial, as they absorb sweat, which lowers the humidity between the fabric and your body, creating a cooler feeling,’ says Dr Lindsay Browning, sleep specialist for And So to Bed.

Sleep is triggered when our internal body temperature starts to fall, ‘and you can encourage this by taking a warm shower or even a hot foot bath about 1-2 hours before bed’, says Dr Kat Lederle, sleep and circadian rhythm specialist at The London General Practice. Although a cool shower might feel more appealing on a hot, sticky evening, ‘the picture here is not so clear,’ says Kat. ‘But with my scientist hat on I’d say run an experiment and find out which works – or doesn’t work – best for you. The key to handling many sleep problems is to be curious about what affects sleep, pay attention to what disrupts it and change what you can, but not to put too much pressure on yourself.’

To try and keep us cooler in summer (or warmer in winter), bedding companies are now embedding tiny particles of a substance called graphene into bedding. Graphene is a heat conductor, and in summer it absorbs excess body heat, wicking it away from the body to keep you at a temperature more conducive to sleep. Take a look at the iGel range from Bensons for Beds, which includes pillows, mattresses and protectors for both, or products by Protect-A-Bed.

There are a number of foods that can help improve sleep, but dietitian Jo Travers from Discover Great Veg names her top six as kale, oil-rich fish, beans, lentils, nuts and sour cherries, which all include nutrients that support the production of two important sleep hormones – melatonin and serotonin. ‘Oily fish, for example, contains omega-3, which is an important part of the pineal gland, where melatonin is produced,’ explains Jo. ‘Beans and lentils include both tryptophan and carbohydrates and this combination helps extra serotonin and melatonin to be made, while sour cherries actually contain melatonin. Several studies have shown that eating these, or drinking sour cherry juice, can improve sleep – especially in older adults.’

Our sleep cycle is ruled by light, and studies show that people who get more natural light during the day sleep better at night. ‘Morning light is the most powerful of all for resetting our circadian clock,’ says Kat. ‘If you see light around the same time each morning, it keeps you on a regular rhythm.’ Start the habit of drinking your coffee in the garden, or going for a walk each morning to help your body get light when it needs it most. Keep getting doses of daylight for the rest of the day – even just through the windows – then start to dim things as you get closer to bedtime.

Studies on miners working in western Australia, one of the hottest areas on Earth, found lowering bedroom temperatures to 16-20°C at night helped them get the best sleep. While you might think this means opening the windows, this can actually make the room hotter, as sunlight and warm breezes can heat the room. ‘Closing the curtains or using blackout blinds during the day can keep the room cooler,‘ says Sophie. She also suggests that if it’s really hot, and you have a spare room on the east of the house, or on a lower floor, you might consider switching your sleep space. ‘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.’

‘Think about putting socks, or your pillow case, in a plastic bag in the freezer and pop them on just before bed,’ says Lindsay. ‘The sensation of coolness can be relaxing and help you drift off.’ Your feet are also the key to a quick cool down if you get hot in the middle of the night. According to US-based sleep specialist Dr Michael Breus, because the soles of the feet have no hairs on them, they lose heat faster than most other parts of the body – making sticking your feet out of the sheets one of the fastest ways to cool down.

If you’re sharing a bed with your partner, you’re going to be warmed by their body heat as well as your own. ‘It can help to have separate top sheets or duvets during summer, as this helps prevent heat transfer,’ says Sophie.

If you’re sleeping with windows open, your sleep could be disturbed by outside noise, like the neighbours’ barbecue. ‘Fans or white noise can have positive effects and mask sudden noises that can wake you up,’ says Lindsay. She also recommends earplugs for light sleepers. Another benefit of a fan is that the room temperature can be 3-4 degrees higher before you start to feel uncomfortable when using one than when not, say researchers at the University of Sydney.

In her book Sleepless: Discovering the Power of the Night Self (John Murray, £10.99), author Annabel Abbs talks about how changing her mental attitude to sleeping less, treating it as ‘a luxurious gift of extra time’, helped her overcome her insomnia. While you might not want to go stargazing or night swimming as she did, changing your attitude to being awake will help even in the comfort of your bedroom. ‘One of the most common causes of insomnia is anxiety,’ says Lydia. ‘If you go to bed worrying that you can’t sleep, chances are you won’t. Instead, get really comfy in bed, find a spot to focus your eyes on, and then just start thinking about how you want to stay awake. But you won’t! By reducing the performance anxiety about falling asleep you relax and eventually drift off.’