Stand up office, any tips?

I would get so tired when I first started using a standup desk. Now I feel great and its amazing exercise for me, as I pace all day and wander around while I work. Xeni works from my place sometimes and we compare Fitbit trackers after a day of her working from my dining room table and me at the standup desk. I walk almost 5mi a day before I leave the house.

Xeni now has an AMAZING treadmill desk that is listed in the gift guide. She tells me it is changing her life.