The world is divided into two camps - those who sleep on the left and those who sleep on the right side of the bed and most of us wouldn't dream of switching sides.
And rightly so, considering new research has revealed there is indeed a correct side of the bed to sleep on.
The Sleep Charity has revealed new data for National Bed Month revealing how to determine the right side of the bed for you.
The data, compiled for National Bed Month, from a survey of 2,000 UK adults by The Sleep Charity and National Bed Federation, revealed that men are more accommodating than women when it comes to choosing a side of the bed.
Turns out there's some chivalry involved in choosing a side of the bed with 36% of men letting their partner choose which side they'd like to sleep on, compared to just 22% of women.
Interestingly men tend to opt for the left hand side of the bed, while women were found to be creatures of habit, with over half (54%) choosing their side of the bed simply because they have always slept on that side.
Other reasons for opting for one side over the other include their partner’s preference (36%) and closeness to the bedroom door (24%).
Men were also revealed to be more superstitious sleepers than women, with 15% of men saying they are guided by superstition when choosing their sleeping side, compared to just 10% of women.
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Choosing a side of the bed based on superstitions is also more commonplace in younger adults, with a third of 18–24-year-olds doing so.
London was found to be the most superstitious area, with just over a fifth (21%) of Londoners allowing their feelings to dictate which side of the bed they sleep on, compared to just 5% of those in Wales.
The location of our technology seems to play a role in our side-choosing decisions too with 43% of18–24-year-olds choosing their side of the bed because of a better view of the TV.
What does having a preferred side mean?
It seems having a preferred side of the bed comes down to our personality type and how our brain is wired.
"There is research to suggest that it is more than just a habit and people who sleep on the left side wake up in a more positive mood, calmer and feel more confident in general than people who choose to sleep on the right side," explains psychologist Aaron Surtees from subconsciously.com.
"People who sleep on the right, on the other hand, are believed to be grumpier and have a less positive outlook on the world."
Surtees says practical elements for picking a side of the bed can also come into play – for instance – on a subconscious level people will generally feel safer sleeping next to a wall instead of a window and it can also depend on how your room is laid out or noise.
"It could also be a case of your partner having a strong preference on which side of the bed they insist on sleeping and not wanting to upset them," he adds.
The Sleep Charity deputy CEO Lisa Artis agrees that often having a preferred side of the bed is less about the side itself, and more about the practicalities of your room layout, with some people preferring a certain side because it is closest to the bathroom or nearer to children.
"While psychology may play some role here, and certainly superstition has been shown to be a factor, we think it’s more about people picking their favourite side because it’s close to the door or for other practical reasons," she explains.
"Physically, it is often the case that we get used to a side through comfort, and I suppose the subconsciously we may develop an attachment due to muscle memory.
"Sleeping in a certain position becomes familiar and comfortable, so we find it unusual if we sleep on the opposite side."
For those who don't have a preferred side, who even are you?, Artis says it's worth trying out both sides to see which suits you better.
“We recommend testing your sleep environment and trying out different positions and conditions to determine the perfect sleep environment for you and your body,” she adds.