Standing Desk

I've been reading a little about the benefits of standing versus sitting. Apparently this is well known in the occupational therapy community. I'm trying to convert to working standing up. My s-i-l A__ has done this recently. Here is my attempt in my home office. That's a table on top of my desk and a music stand with the iPad on the left.

No surprise, my legs feel it. I have to concentrate on posture or my lower back feels it. I do find myself fidgeting around to make the position comfortable. Concentration seems easier -- perhaps because nervous energy is used in my maintaining my posture rather than through my mind's wandering? Verdict after two hours? So far so good.