Why do we need to sleep with a blanket or sheet - even when it's boiling?

In case you hadn’t noticed, the UK is currently in the grips of a heatwave and sweltering in record breaking temperatures.

While the hot weather is nice and all, it brings with it some issues, and topping the list is the inability to sleep in the heat.

But, despite the fact that we’re absolutely roasting many of us still refuse to ditch our duvets.

Whether we’re full on snuggled or need to have the smallest edge draped over one leg, some people simply can’t drop off unless they’ve got some kind of blanket, sheet or duvet covering us.

So, where does the whole cover compulsion come from?

Science offers one explanation as to why we just can’t ditch the bed covers, even in 90+ temps.

Firstly, whether you realise it or not your body’s core temperature drops before and during your slumber, so subconsciously you might feel you need the blanket to stop you getting cold.

READ MORE: 9 heatwave mistakes we're all making

The nightly body cool down starts about an hour before lights out and continues to drop while you sleep, eventually reaching one or two degrees below your average body temperature.

But once you reach the rapid eye movement (REM) sleep cycle, your body is no longer able to regulate its temperature.

Therefore your blanket acts as a necessary vessel to keep your body toasty - even on a hot summer’s night.

Click below for the best fans under £20 to see you through the UK heatwave:

The other thing that happens during REM periods of sleep is the serotonin levels in our bodies lower. Serotonin, often referred to as the happy hormone, is the neurotransmitter most associated with feelings of calm, happiness, and wellbeing.

Interestingly various studies have linked sleeping with a weighted blanket with higher levels of serotonin, suggesting that they can curb anxiety and even be used in the treatment of autism.

“A weighted blanket moulds to your body like a warm hug, while the pressure also helps relax the nervous system,” one study explains.

READ MORE: What happens to your body when it gets too hot?

It works in a similar way that swaddling can comfort an infant.

According to James Wilson aka The Sleep Geek there’s also a behavioural element to sleeping with your duvet on even in the sweatiest of times. It’s all to do with the fact that we’ve been conditioned to use blankets since birth.

“I think there is a behavioural aspect from childhood, it is what we are used to therefore if it's not there we don’t feel as secure,” he explains.

In other words we remember being tucked in bed with a blanket when we were children and now associate that with going to sleep.

“Sleeping well is about feeling physically and emotionally secure and for many of us a blanket or a duvet plays a big part in that.”

If you’re struggling to sidestep the bed clothes even in the heat Wilson suggests you switch up your security blanket.

“My advice at this time of year is to use either a low thread count or cotton sheet or preferably a bamboo one,” he advises.

“And if using a duvet, look at one made from Alpaca fleece, as the fleece of the alpaca is incredibly efficient at absorbing and wicking away moisture.'