Britons have resorted to buying electric fans in a bid to stay comfortable at home. However, experts are now warning against leaving the appliances on all night.

       Asthma sufferers, as well as those with allergies, are advised against leaving their fans on while they sleep as they can disseminate dust and pollen.

       The Sleep Advisor said: “Take a close look at your fan. If it's been collecting dust on the blades, those particles are flying through the air every time you turn it on.”

       Leaving fans on overnight can also affect the health and appearance of skin, eyes and mouth.

       Muscles can also suffer from sleeping with a fan on as it can cause stiffness.

       Those who sleep with the fan facing their neck and face could particularly feel this.

       The Sleep Advisor said: “This is because the concentrated cool air can make muscles tense up and cramp.”

       There are currently two extreme weather warnings in place that will remain in force until Friday.

       The Met Office has warned of a risk to life as Britain faces a heatwave until the weekend.

       Speaking on BBC Breakfast, weather presenter Carol Kirkwood highlighted how a second extreme weather warning has been introduced in Northern Ireland on Wednesday.

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