Sitting at a desk or computer terminal for extended periods of time can cause muscular tension and pain. Frequent short stretch breaks can reduce tension, head and muscle aches, and increase productivity and make work a more pleasant place to be. Take a short stretch break 30 minutes or so. And remember the 20/20 rule. Take your eyes off of your computer screen for 20 seconds every 20 minutes. Focus on an object far from the computer screen.