Office Work is Dangerous!
The British Journal of Sports Medicine has identified further evidence that prolonged sitting or standing in stationary positions is increasing the risk of heart disease and diabetes (at least). They say there has been an alarming decrease in the amount of mild activity people undertake. So guidance is to encourage staff to spend at least two hours of every day moving around or changing positions. It's a bit like the need to take micro-pauses to avoid RSI.
Now you need to encourage jobs that require some movements - such as to the printer. And make sure that smoko and lunch is not taken at their desks - that can be 1-1.5 hours of each day in itself!