I’ve got a treadmill walking desk - two, actually. I’m in a bit of a unique situation where I do two types of jobs on my computer. I do both photography and some development. I can do all my photography tasks while walking at a fairly slow pace, 2mph or so. I’ll often walk 4 or 5 hours a day. I can’t, however, concentrate on an audiobook at the same time while culling photos. Editing and retouching are so automatic I can do all three.

Programming though? Only if I’m doing something I know how to do fairly well I can walk. That’s pretty rare due to how little time I can commit to coding.

In either situation it keeps me more awake and energized, even if I can’t concentrate as well.