In recent decades, lifestyle medicine has focused not only on what we eat or how much exercise we do, but also on something much more everyday and seemingly trivial: the way we sit.

Sedentary behavior has become one of the great silent epidemics of the century In the 21st century, the study of the postures we adopt for hours in front of screens, at work desks, or on public transportation has become increasingly important. In this context, specialists in physiotherapy, orthopedics, and biomechanics have begun to pay special attention to a reflexive gesture that millions of people perform almost unconsciously: crossing their legs when sitting. This favorite posture of many in the office, at the cafe, or on the sofa has consequences for circulation, bones, nerves, and even male fertility. Experts warn: the problem is not doing it occasionally, but making it a habit. Sitting with crossed legs: According to a study by Professor Michael Reiss of the Dresden University of Technology, approximately 62% of people cross their legs from right to left, 26% in the opposite direction, and only the remaining 12% have no preference. We do it in the doctor's waiting room, in front of the computer, in a meeting, or while having coffee. The question is: are we paying for it with our health?

The answer, according to the available scientific evidence, is that it depends. Not on the gesture itself, but on its frequency and duration.

A Pressure the Heart Feels

One of the most documented effects of crossing your legs—especially at the knee, which is the most common way—is the impact on blood pressure. By placing one leg over the other, the venous network of the lower extremities is compressed, making it harder for blood to return to the heart. To compensate, the heart has to work harder, which translates into an increase in blood pressure.

This effect is so well-recognized in medicine that it constitutes a basic clinical criterion: when a patient's blood pressure is measured,The standard medical protocol indicates that both feet should be flat on the floor. If it is done with the legs crossed, the result will be inaccurate and probably higher than it should be.

For people with chronic venous insufficiency or varicose veins, this posture can increase the risk of damage to blood vessels and the formation of clots, potentially leading to thrombosis. This is not a hypothetical threat: it is a measured and documented consequence of this sustained habit.

The spine pays the price

Beyond the circulatory system, the skeletal impact is perhaps the most popular among those who chronically adopt this posture.

Sitting with one leg crossed over the other causes uneven hip rotation, which can lead to a lateral pelvic tilt and spinal misalignment, generating tension and pain in the lower, middle, and upper back, as well as the neck. The human body is a compensatory machine. When the pelvis becomes misaligned, the spine detects it and reacts by adjusting to maintain a stable center of gravity, triggering a chain reaction: the shoulders round, the head juts forward, and the neck muscles tense up. Studies show that the longer and more often this posture is adopted, the more likely long-term changes are to occur in the length of the muscles and the arrangement of the pelvic bones. Over the years, if left uncorrected, this imbalance can contribute to the development of scoliosis and other more significant postural deformities. The Complaining Nerve There's a technical name that physiotherapists often use when discussing this habit: the peroneal nerve, also called the fibular nerve. It's a branch of the sciatic nerve that runs along the outside of the knee and leg, and is exposed to direct compression when we cross our legs at that joint. Research shows that this posture can put the peroneal nerve at risk of compression and injury, which usually manifests as weakness when trying to lift the side of the little toe or, in more severe cases, complete foot drop. Although in most cases the effects are short-lived and disappear within a few minutes, the risk increases with prolonged exposure. The tingling and numbness that almost all of us have experienced when getting up after sitting with our legs crossed for a while is precisely this nerve compression at work. The difference between a temporary effect and permanent damage lies in...Once again, in accumulated time.

Hips, knees, and a syndrome few know about

Keeping your legs crossed for extended periods can put excessive pressure on the hip joints, hindering their natural relaxation. This constant tension can lead to chronic pain and decreased muscle strength in the area, as well as increasing the risk of greater trochanteric pain syndrome, a condition that affects the outer part of the hip and thigh.

Knees aren't spared either.When you cross your legs, the ligaments and muscles surrounding this joint are subjected to additional tension, increasing internal pressure and promoting pain, especially in those who already have a pre-existing condition in that area.

Impact on male fertility

Among the most surprising findings of the research is its potential impact on male fertility. The temperature of the testicles must be kept between two and six degrees Celsius below normal body temperature to ensure optimal sperm production. Sitting already increases testicular temperature by around two degrees, and crossing your legs can raise it by an additional 3.5 degrees. Several studies suggest that this temperature increase can reduce both sperm count and quality.