Two frightening harmful effects of the habit of sitting with crossed legs.

I often sit with my legs crossed at work and frequently experience numbness in my legs. I've read online that this posture is bad for the spine and joints. Could you please advise us on the best way for office workers to sit to improve our health, avoid harming our joints and eyesight while working? Thank you, doctor. (Vo Thanh Thao, Go Vap District, Ho Chi Minh City)

Dr. Pham Anh Ngan - University Medical Center of Ho Chi Minh City, Branch 3, answers:

The habit of sitting with legs crossed is common among women, due to beauty standards of elegance, as seen in paintings and photographs of Asian and European women throughout history. However, this sitting posture has certain harmful effects on the body.

The first,Impact on the nervous and vascular systems: Sitting with crossed legs alters blood flow pressure, affecting the nerves supplied by nearby blood vessels. Prolonged sitting compresses the nerves, causing symptoms such as numbness, paresthesia, or decreased sensation.

Sitting with your legs crossed is harmful to blood vessels and joints.

Changes in pressure also contribute to the formation of spider-like venous networks in the legs. Studies have also shown that crossing legs increases both systolic and diastolic blood pressure by 8-10 mmHg in patients with hypertension.

MondayImpact on the musculoskeletal system: Sitting with crossed legs not only affects the weight-bearing knee joint and the collateral ligaments, but also the collateral ligaments of the knee joint, which are subjected to prolonged compression.

According to research, when we stand, the force is evenly distributed on both sides of the hip joint, while when we sit, the force is evenly distributed on both sides of the pelvis. If we sit with our legs crossed, the position of the pelvis changes, and the pressure on the gluteal muscles also changes. This is also a cause of back pain conditions such as sciatic nerve compression or piriformis syndrome.

In addition, the ligaments holding the sacrum and pelvis are also strained when the pelvis is tilted, which over time risks disrupting the natural curvature of the spine and affecting even the upper vertebrae.

Sitting with legs crossed should not be maintained for extended periods; it is necessary to frequently change to sitting with both legs straight to avoid harmful effects on the body.

To protect your joints, when sitting at work you should choose a comfortable but correct posture. Place your feet on the ground at a 90-degree angle to the desk. Your knees should be level with your hips, avoid putting pressure on the chair, and do not sit with one leg bent.

You should maintain an upright posture, tilting your head back slightly. If your chair reclines deeply, you should use a neck and shoulder support cushion to reduce neck and shoulder strain. Ensure your forearms and upper arms form a 90-degree angle to minimize pressure on your shoulders and wrists during long periods of work. The distance from your eyes to the computer screen should be 50cm. Sitting upright also helps maintain good posture and prevents spinal problems, especially in middle-aged and older adults.