How do you like to sit on a chair? Many people prefer to cross one leg over the other. In the 1980s, British comedian Kenny Everett even made it his trademark – extravagantly crossing, uncrossing, then recrossing his legs while dressed in a skirt and high heels, declaring it was “all in the best possible taste”. 
 
 Others prefer not to cross their legs at all and even to “man spread” as it’s become known, sitting with their knees wide apart on public transport while the people either side of them are squashed. These men might have liked a rather curious publicity campaign launched in the US in 1999 called “The Great Cross-Out” where a dietary supplement company encouraged people to keep healthy by not crossing their legs for a whole day. 
 
 The list of suggested consequences includes raised blood pressure, varicose veins and nerve damage, but is it true? 
 
 But is it really any healthier to avoid crossing your legs? The list of suggested consequences of spending too much time with one knee crossed over the other includes raised blood pressure, varicose veins and nerve damage, but each of these deserves close examination. 
 
 Of course it is true that if you spend too much time in exactly the same position, eventually your leg or your foot can go numb. This is because crossing the legs can put pressure on the peroneal nerve behind the knee, which supplies sensation to the lower legs and feet. But if you do give yourself pins and needles this way, it is only temporary. 
 
 Maintaining a particular posture for many, many hours can however lead to a condition called peroneal nerve palsy resulting in “foot drop” where you can’t lift the front part of your foot and toes. But when a study from South Korea examined a series of patients’ notes in order to identify the chief causes, sitting on a chair with one knee over the other didn’t feature. Sitting cross-legged on the floor for hours at a time did. In reality long term numbness is an unlikely consequence of leg-crossing because as soon as we feel uncomfortable we tend to move. 
 
 So how about blood pressure? When you get it checked, the doctor or nurse tends to ask you to rest your arm on the chair or table and to uncross your legs, putting your feet flat on the floor. The fear is that crossed legs might skew the reading by temporarily raising your blood pressure. By 2010, seven studies had indeed found that leg crossing does result in a higher blood pressure reading, while another study found it made no difference. However, many of these studies were small and relied on taking a blood pressure reading just once. One of the larger studies was conducted at a hypertension clinic in Istanbul. Researchers there took several readings with legs crossed and uncrossed. Again, blood pressure was higher when legs were crossed, but crucially when the measurements were repeated just three minutes after uncrossing the legs, blood pressure was back to the earlier levels. The greatest rise in blood pressure occurs in people already being treated for high blood pressure. 
 
 Two possible mechanisms have been proposed to explain why leg-crossing might lead to a temporary rise in blood pressure. One is that the action of putting one knee over the other sends blood from the legs up to the chest resulting in an increased quantity of blood being pumped out of the heart, raising blood pressure. An alternative explanation is that blood pressure rises because isometric exercise of the leg muscles (exercise without the joints moving) increases the resistance to the blood passing through the vessels. This might explain why crossing legs at the ankles doesn’t have the same effect. 
 
 In order to establish which of these explanations was the most likely, a study in Nijmegen in the Netherlands took a number of physiological measurements. The team found that resistance in the blood vessels didn’t rise when the heart rate was low and the legs were crossed, but the amount of blood leaving the heart did, suggesting that the increased blood pressure is due to crossed legs pushing blood up to the heart. 
 
 So crossing the legs does appear to cause a temporary rise in blood pressure, but the evidence for any long-term consequences simply isn’t there, with one exception. People at high risk of blood clots are advised not to cross their legs for long periods of time because for them, impeding the flow of blood could increase their risk of a deep vein thrombosis. 
 
 But even if crossing your legs doesn’t give you high blood pressure in the long term, what about the idea that it can give you varicose veins? The reasons why some people suffer from varicose veins and others don’t is something of a mystery. Usually tiny valves in the blood vessels prevent blood from flowing back in the wrong direction, but if those valves become stretched and weakened the blood can pool, resulting in the enlarged veins we call varicose veins. Crossing the legs has not been demonstrated to be a crucial factor. Whether or not you get varicose veins seems, partly at least, to be down to genetics. 
 
 One study found that people who sat with their legs crossed for more than three hours a day had poor posture 
 
 So if veins, blood pressure and nerves are not affected by leg-crossing in the long-term, how about the impact on our joints? One study found that people who sat with their legs crossed for more than three hours a day were more likely to lean forward and to round their shoulders. But the research relied on people’s own estimations of how long they crossed their legs for. As I write this, I’m sitting at my desk and happen to have my legs crossed, but I would have no idea how many hours a day I spend sitting in this way. More recent research published this year found that if people were instructed to sit up straight while they crossed their legs the postural problems were overcome. Of course whether that’s maintained when you have no experimenter standing over you is another matter. Incidentally almost twice as many people reported crossing their right leg over their left knee than the other way around. 
 
 Slouching doesn’t sound good, but if you are fan of leg-crossing, you might like a rather curious study from the University Medical Centre in Rotterdam which found that it could bring benefits. Researchers examined young men and women as they sat with their legs either straight, crossed at the knee or crossed at both the knee and the ankle at once. They then simulated the exact angles of the posture in four embalmed pelvises, which allowed them to measure exactly what our muscles do when we cross our legs. They found that crossing the legs at the knee increased elongation in the piriformis muscle running behind the hip joint by 11% when compared with sitting with legs uncrossed, and by 21% when compared with standing (interestingly the tension was slightly less if the legs were crossed at the ankle too). The authors believe that this increases stability in their pelvic joints in a similar way to tensing the abdominal muscles does. 
 
 So if you like crossing your legs Kenny Everett-style then you’re unlikely to do yourself any damage, provided you don’t stay in the same position until your legs are numb. And whoever is sitting next to you on the bus or the train will be grateful to you for taking up less room than the man-spreaders. 
 
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 This common way to sit actually comes with health risks. (Photo: Stocksy/Jill Chen) 
 
 
 
 You probably cross your legs at least once while you’re having dinner, working at your desk, or pretty much any time you sit down. Odds are, you don’t even realize you’re doing it — you just sit and cross one leg over the other, like you’ve done for years. 
 
 But experts say you might want to rethink that habit: Crossing your legs can actually have some negative health effects. Here’s what you need to know: 
 
 It Causes Back And Neck Pain 
 
 
 
 In a perfect world, you’d sit facing forward with both feet planted squarely on the floor. Unfortunately, that rarely happens. Most of us shift our weight around, lean to one side or the other, or, yup, cross our legs. 
 
 According to orthopedic physical therapist Vivian Eisenstadt, crossing your legs is just asking for back and neck pain. Sitting with your legs crossed puts your hips in a torqued position, which can lead to the rotation of one of your pelvic bones, she explains. Since your pelvis is the base of support for your spine, it puts unnecessary pressure on your neck and lower and middle back when it’s rotated and unstable. And the longer you sit with your legs crossed, the more pressure you put on your spine, which increases the odds you’ll develop an issue. 
 
 “Days and weeks of doing this are one of the main reasons we have back and neck pain, as well as herniated discs,” she tells Yahoo Health. 
 
 While it’s unrealistic that you’ll have perfect posture every time you sit down, she recommends sitting with your knees and ankles at 90 degrees with your pelvis balanced whenever possible. 
 
 Related: 8 Everyday Things That Cause Pain 
 
 It’s (Possibly) Linked To Spider Veins 
 
 No one wants spider veins, but they happen — according to the U.S. Department of Health and Human Services, about 55 percent of women and 45 percent of men in the U.S. have them. 
 
 The medical community seems to be divided on the link between crossing your legs and spider veins. While some doctors say spider veins are solely caused by genetics, pregnancy, sun exposure, and frequently standing or sitting for long periods of time, others like Hooman Madyoon, MD, a cardiologist at Cedars Sinai Medical Center who specializes in the treatment of venous diseases, tells Yahoo Health that there is an indirect link between the two. 
 
 He explains how it works: Crossing your legs increases the pressure on your veins that are responsible for returning blood back to your heart. The pressure of one leg on top of the other impedes your blood flow, which can weaken or damage the veins in your legs. If the veins are damaged or weakened, the blood can leak into them and collect there, causing spider veins or exacerbating existing ones. 
 
 
 
 It Elevates Your Blood Pressure 
 
 It’s surprising, but true. Crossing your legs at the knee can temporarily cause your blood pressure to go up. 
 
 Here’s why: The blood in your legs has to be pumped back to your heart against gravity, explains Madyoon. That’s already a tough enough task for your body, but when you cross one leg over the other, it increases resistance to the blood flow. As a result, your body has to increase your blood pressure in order to push your blood back up to your heart. 
 
 You usually won’t feel any symptoms when your blood pressure goes up, but repeated, drawn-out increases in blood pressure can cause long-term health issues. So, planning to sit for a long period of time? Don’t keep your legs crossed. 
 
 Related: 8 Ways To Lower Your Blood Pressure Naturally 
 
 It Messes With The Nerves In Your Feet 
 
 Crossing your legs doesn’t just impact the blood flowing back up to your heart—it affects the veins and nerves in your legs and feet, too. 
 
 Crossing your legs at the knee can cause pressure on your peroneal nerve, the major nerve in your leg that passes just below your knee and along the outside of your leg, explains Richard Graves, a podiatrist who specializes in disorders of the lower extremities. This pressure can cause numbness and temporary paralysis of some of the muscles in your foot and leg, preventing you from being able to raise your ankle — what we know as that “pins and needles” sensation. 
 
 While the feeling is only temporary, Graves says repeatedly sitting with your legs crossed in the same position can also cause you to develop long-term numbness in your legs from nerve damage. 
 
 Read More 

 Fainting can be a frightening and dangerous experience, sending as many as four million people to the emergency room each year. 
 
 Now, with an aging population that is more vulnerable to such episodes, often on a recurrent basis, hospitals are trying to do a better job of identifying the causes of fainting, known in medical terms as syncope, and determining which cases are serious enough to warrant follow-up and hospitalization. 
 
 ...
– If you sit with your legs crossed on a regular basis, it might be time to stop feeling so guilty about it. While there are a few specific exceptions, crossing one's legs at the knee or the ankle doesn't appear to be as bad for our health as some experts have said. Analyzing studies that have looked for links to varicose veins, nerve damage, and elevated blood pressure, the BBC reports that the science shows "you’re unlikely to do yourself any damage, provided you don’t stay in the same position until your legs are numb." First, sitting in one position for many hours without moving can lead to a condition known as "peroneal nerve palsy," but this is true for any pose. Second, while most studies do find a momentary elevation in blood pressure when crossing one's legs at the knee, it goes away quickly and unless you're at a high risk of blood clots, there doesn't appear to be any long-term harm. As for what causes varicose veins, experts disagree, with some pointing to genetics and others saying that leg crossing can lead to damaged veins into which blood can leak and pool, reports Yahoo. Meanwhile, the Wall Street Journal notes that leg-crossing is among the simple solutions to the human fainting response offered up by doctors studying the issue. In other words, the jury's still out, but leg crossing doesn't appear to be particularly pernicious. (One researcher proposes a series of sitting, standing, and stretching while we work.)