Having had 4 spinal surgeries, and sustained a lot of back injuries, I can tell you that posture is very important. I was also told that the best thing you can do for your posture is to take that break, every hour, get up and walk around a little bit -- I've never timed how long I stay away from my chair, but I took longer than just getting a drink of water or going to the bathroom -- long enough so that you can relax those tense muscles. My orthopedic physician also told me this, but my boss at the time, said, yes, you can get up and walk around your desk, then turn around, sit down and get back to work --scrooge!