• Cast aside your pyjamas and sleep naked if possible. If you do tend to get very hot and sweaty, then drape a beach towel over the bed and pillows to protect the bedding.

• Open the windows - preferably more than one, on different sides of the house - to allow more air to circulate. But this may not be advisable if you are in a bungalow, ground-floor flat or basement, because of the higher risk of burglary, so check the other options for ideas. You might also be concerned that throwing open the windows will let in more noise from the street - one way around that is wearing earplugs as long as you can still hear your alarm clock go off in the morning.

• Have a lukewarm shower before getting into bed. Best to avoid an ice-cold shower, as your body will compensate afterwards by raising your temperature. Get into a shower that's set at your normal temperature, so it's not too much of a shock, and then gradually turn it down until it's tepid or cool, but don't go as far as freezing cold.

• Bring an electric fan into the room to blow cool air over over you. These fans are rarely silent but you will get used to the noise after a while. Sleep scientists have said an electric fan is the most sensible option for getting to sleep on a hot night. In the longer term, you could consider getting a ceiling fan installed.

• If you don't already have a combi boiler that heats water as you need it, reduce the amount of time your water heating system is on. A tank of hot water upstairs will radiate heat, even with good insulation, and will only warm up that part of the house even more. Lukewarm showers should mean needing much less hot water than usual, so alter your timer accordingly. In this weather, a single person should not need the hot water to be on for more than an hour at night and half an hour in the morning.

• Use a summer duvet with a lower tog rating, or abandon the duvet altogether and opt for a thin cotton sheet, which will absorb perspiration. Drape the sheet over the bed and sleep on top - you can always pull it around you during the darkest, coolest parts of the night.

• Turn over your pillow every now and then so you are resting your head on the cooler side.

• Keep blinds, curtains or shutters closed during the day on the side of the house where the sun is shining.

• Put a glass of iced water near your bed so you can have a sip if you wake up feeling hot or dehydrated during the night, and keep cool in the time you are trying to fall asleep.

• In extreme temperatures, or for people who become very overheated and unable to nod off, items soaked in cold water can be used to help you sleep. Soak a flannel (face cloth) in cold water, wring it out and then lay it on exposed flesh. Some people have even admitted they wear wet socks or a wet T-shirt to bed - wring them out first, of course. Another option is to dip a sheet in cold water, wring out the excess and lay it on you, while others recommend putting the pillowcases and sheet in the freezer all day.

• Fill a spray bottle with cold water to spritz yourself while lying in bed.

• Take a cool-box ice-pack to bed, wrapped in a pillow case, and put your feet or body against it in much the same way you would use a hot water bottle.

• Another suggestion for keeping the upstairs cool is to open the hatch to the loft so that heat can rise further and escape from the house.

• But if the upstairs still proves too unbearably hot after trying our other ideas, you might want to temporarily sleep downstairs on a folding bed or sun-lounger (which allows air to circulate around you more freely). Best to place the bed on a cool, tiled floor.

• Plunge both your wrists into a deep bowl of very cold water and hold them there until your body cools down, or hold them under the cold tap for a few seconds.

Source - http://www.birminghammail.co.uk/news/health/how-sleep-hot-weather-cool-5104529