Buy backpacks, exercise machines, athletic shoes, and more at Fogdog Sports. It is considered a type of repetitive stress injury, since it's often associated with jobs or other activities that call for repeated movements of the hand and wrist. Many other physical conditions may cause or contribute to it as well, including pregnancy, obesity, diabetes, and certain autoimmune diseases. If the tendons in and around the tunnel get swollen, they may pinch the median nerve, the major nerve passing through the carpal tunnel. That can cause pain, numbness, and other problems.
Posture also appears to play a role.
Studies show that arching your wrist, bending your wrist repeatedly, or extending your arm outward from your body increases the pressure in the carpal tunnel. Some people, especially women, are more prone to this condition. Many researchers believe that people with such conditions develop the syndrome more readily if they also overuse their hands and wrists. The symptoms usually appear for at least a week or may flare up intermittently for more than a month. Pain in your hands or forearms that often gets worse at night or after you use your hands.