excellent idea on walking ...

and let me make this suggestion.

BUY a pedometer ... something that counts steps.
I know that at first glance the idea seems somewhat ridiculous. But I use one now - and have found it to be very effective. The REASON it works ... is that pretty soon you find yourself making a daily goal to do a certain number of steps (say 10,000 steps in a day, or 12,000). By the way, for average work days, its not so easy to get to 10,000 steps!!

anyway, the point is that the pedometer gives you an accurate number to work from. Pretty soon, you find yourself getting up off your office chair and walking around - just so you can increase your step count. After that, you start taking the LONG way to every conceivable destination ... just to increase the step count. And basically, you wind up with a whole lifestyle change where you are just doing MUCH more walking!!

cheers,
Pete