Office ergonomics: Get off your rump once in a while
Sitting for long periods of time puts pressure on the disks in your lower back and can disrupt circulation in your muscles. Also, holding the same position for long periods of time can cause repetitive strain injury.
It is a good idea to stand up and stretch every 20 minutes for at least 20 seconds, according to Circadian Technologies. Using an ergonomically sound chair can also help.