When was the last time someone told you to uncross your legs? Probably not since you were a child (although, sidebar: don’t cross your legs at the hairdressers if you’re after straight bangs). And, as usual, your mum was onto something – sitting with your legs crossed can be bad for your health.

So, make sure you’re sitting comfortably – with both feet flat on the floor – and let’s take a look at the science. 

Why do we cross our legs?

For many of us, crossing our legs when we’re seated feels natural and comfortable, whether that’s crossing at the ankle or one leg over the other. And with good reason: in Western cultures, sitting with legs crossed is linked closely with morality and etiquette, particularly for women; conversely, in some Middle Eastern countries, it can be seen as a sign of disrespect. And it is physically easier for women to cross their legs than men, who don’t have the same range of movement in their hips. 

Politeness aside, crossing our legs has a mechanical function. When we’re seated in a chair, crossing our legs serves to shift our bodies backwards, taking the strain off the lower back as our lumbar spine is more supported, hence why it can feel more comfortable.  

“Crossing our legs allows our muscles to relax so it feels good,” Barbara Kerr, founder of Transform Body and Mind, tells Stylist. “It takes the pressure off the abdominals and core, so it can feel pleasant.”

In addition, some studies show that the simple movement of crossing our legs can help our brains to function better due to the ambidexterity required.

And it’s also a learned behaviour, meaning that it could be hard to break the habit. So, what’s the problem? 

Why is it bad for us?

According to Professor Adam Taylor from the University of Lancaster, there are number of reasons why sitting cross-legged is a no-no.

“Research shows that sitting cross-legged can increase blood pressure and risk of blood clots,” he writes in The Conversation. “It can cause damage to the blood vessels and, over a long period of time, it can even cause deformities of the spine and posture.”

Blood pressure issues

If you’ve ever wondered why you are advised to have both feel flat on the floor while having your blood pressure read, here’s why. 

“Sitting [with legs crossed] this way can cause an increase in your blood pressure due to the pooling of blood in the veins and your heart having to work against this,” explains Taylor. “This can increase the risk of damage to your blood vessels, and it changes the speed at which blood moves through the blood vessels in the lower limbs, which can increase the risk of blood clots.”

Postural issues

When our legs are contorted around each other, our bodies become misaligned from the neck right through to our hips and pelvis, which over time, can cause potentially serious issues. 

“The longer and more often you sit cross-legged, the more likely it is that you’ll have long-term changes in the muscle lengths and bone arrangements in your pelvis,” says Taylor. “Due to the way your skeleton is linked together, leg crossing can cause misalignment of the spine and shoulders, while your head position can also potentially become out of alignment due to changes in the bones of the neck, as the spine compensates to keep your centre of gravity above the pelvis.”

And if you’re prone to neck pain, you might want to reconsider how you sit, as the strain of sitting cross legged can lead to one side of the body becoming weaker than the other, affecting the muscles of the neck.

It’s particularly bad during pregnancy

Yoga teacher and birth doula Laura Jones advises all her clients not to cross their legs. “It’s the very first piece of advice I give to pregnant women,” she says. “We have two ligaments, simply called the round ligaments, that attach from either side of the uterus to the left and the right side of the pelvis. When we cross our legs, it creates an asymmetry of the pelvis that affects those ligaments as well the deeper muscles of the pelvic floor.

If you’re planning a vaginal birth, you want to make it as easy as possible to pass a baby through your pelvic floor and avoid a lengthy labour. Babies can only get into the position that is available to them.”

What can we do?

The advice from the experts is simple: stop crossing your legs. “It can be quite a hard habit to break,” Jones acknowledges. “Try to notice every time you cross your legs, and then switch position – either put your feet flat on the floor or, if you really want to cross your legs, cross them at the ankle, not higher up.”

“If you are a cross-leg sitter it’s best to get up regularly and move about,” advises Kerr. “Try to swap legs to prevent one side from taking more strain and move as much as you can.”

Images: Getty