
A heatwave is set to sweep the UK this week, with temperatures expected to top 30C in some parts of the country.
But while Brits will be flocking to pub gardens, it won't be long before we're all lying awake sweating and wondering why we wanted the sun in the first place.
And before you dust off last year's fan for bedtime, a sleep expert has warned of the surprising health issues that can come hand in hand with trying to keep cool.
As per the Met Office, pollen levels are expected to reach 'very high' in London and 'high' in the East and South West of England on Sunday, May 25.
Advert
According to sleep therapist Natalie Pennicotte-Collier of MattressNextDay, bedroom fans can cause people's allergies to play up, as they circulate dust and pollen around the room.

"Hay fever and dust allergy sufferers are essentially circulating their primary triggers continuously in a closed bedroom for seven or eight hours," Natalie explains.
This can leave people waking up feeling congested with symptoms including a blocked nose, fatigue and itchy eyes.
Natalie also highlights that it's crucial to clean your fan between uses, as unwanted dust can circulate around your home - not want you want to worry about before hitting the pillow.
From top tips on using a fan during the heatwave to the best fans to buy now, find out more below.
Why you shouldn't leave a fan on overnight
Despite the urge to keep the fan on all night for a bit of relief, it can actually work against you.
Over the years, you might have heard the dangers of using a fan overnight, as it can cause health issues such as dry sinuses, irritated eyes, and allergies.
"What helps you fall asleep is not always what supports your best quality sleep across the whole night," Natalie explains.
Shark ChillPill 3-in-1 Fan

£129
"A fan can ease sleep onset, but as the room cools further in the early hours and your core body temperature begins to change before waking, that same fan can start to fragment your sleep, triggering lighter waking as your body tries to regulate itself."
In fact, a fan can have a negative impact on your body's natural temperature.
According to Natalie, your body needs to warm up slightly in order for you to naturally fall asleep and wake up.
"With a fan running all night, the constant airflow continues to cool and dry the air around you, which can interfere with that natural process," she adds.
Follow the below steps to get the most out of your fan this summer:
- Set a timer for the fan to switch off after a couple of hours
- Point the fan towards the ceiling or a wall to help circulate cooler air around the room
- Clean your fan thoroughly and regularly to reduce the risk of circulating dust and pollen
- Keep the windows closed when pollen levels are high if you have hay fever
Shop our top heatwave picks:
Sukeen Cooling Towels

£12.99
£11.04
Owala FreeSip Water Bottle

£36.99
£28.11
Skin Gym CryoChill Face Mask

£32.17
Handheld Fan with Active Ice Cooler

£19.99
£9.49
Shark FlexBreeze HydroGo Cordless Fan

£129.99
£89
Dyson Cool AM07 Bladeless Tower Fan

£349.99
£299