When working at a computer all day, what's the best way to avoid wrist pain and carpal tunnel syndrome?

A. Although carpal tunnel syndrome has been said to be a consequence of computer work, “it’s important to know that there’s very little evidence that computer use causes carpal tunnel,’’ says Jesse Jupiter, an orthopedic specialist in hand surgery at Massachusetts General Hospital. The condition is caused by compression of a nerve in the wrist, and symptoms include numbness and tingling particularly in the thumb and the fingers closest to it and pain in the arm. While carpal tunnel has been linked to some occupations in which people must forcefully flex and extend the wrist, such as working on an assembly line or in a slaughterhouse, the relatively minor movements of typing and pointing a mouse don’t appear to have the same effect.

More commonly, computer workers suffer from pain and soreness caused by muscle fatigue. Computer work, which often involves repetitive movements while typing or using a mouse, can put strain on the muscles and tendons in hands, wrists, and arms. Jack Dennerlein, director of the Occupational Biomechanics and Ergonomics Laboratory at the Harvard School of Public Health, says that studies on pain and computer use suggest that using a computer mouse, rather than typing, is the main culprit. Most people, he says, spend twice as much time using the mouse when they’re on the computer as they do typing. “When using the mouse, the wrist posture is fairly constrained,’’ he says, and the positioning is not usually ideal, with wrist bent.

The best way to prevent pain and soreness is to give your hands and wrists a break: Get up, move around, stretch, or just engage in different movements than you do at the computer. Dennerlein recommends letting go of the mouse when you’re not using it, much as pianists rest their hands in their laps when not playing. Pain and fatigue result from staying in one position and performing the same movements over and over; varying your posture, desk or seat height, or mouse placement can help.