A few months ago I stacked two tables and put my keyboard and office stuff on the top table. So now I stand all day while doing my computer/office work. The only time I sit down during the day is to eat.
Works great. For about the last decade I've had a problem with some kind of minor sciatica (hip soreness), but it seems to have disappeared since I stacked the tables and started working standing up.
Also, they're starting to manufacture treadmills equipped with flat work surfaces, so that you can walk and do computer/office work at the same time. That would be better yet--actually getting some exercise while you're doing paperwork. I might hunt down one of those and try it out.
I'm necroing an old thread to highlight some new research. A limited study shows that sitting results in a shorter lifespan whereas standing increases longevity. Exercise, meanwhile, improves quality of life (improves overall health) but doesn't have all that much effect on longevity per se. Or at least, exercise didn't affect the particular benchmark or metric (length of telomeres) that they were using as a basis for judging longevity in this particular study.
So according to the study, a longer lifespan is all about reducing your sitting and increasing your time spent on your feet. And then presumably it would also be wise to do some exercise; what good is having a long life if you're out of shape, ill, and have a poor overall quality of life?