If you sit at the desk in front of a computer for most of the day, the neck, forearms and back are in definite danger of becoming too stiff. In my newspaper days, one real estate reporter had carpal tunnel syndrome so bad she wore wrist supports and had a swivel support system for her forearms attached to her keyboard. I never forgot that sight.
Get up and walk (standing straight as if a tight string was pulling you up from the heavens) and grab some water. Stand up and do some side bends and neck twists. Rotate your hips. If you're on the phone a lot, ask your office manager to order you a headset.
Also make sure your keyboard sits comfortably with about a 90-degree bend in your arms. The top of the monitor should hit eye level. These are tips from years of having an ergonomic consultant visit us in the newsroom.
It's bad enough a lot of work in The Office. Let's not let it make us old.