I’ve had a walking desk for years in my home office. It was transformative for me. I found that once my body adjusted to walking I would go I to flow and find a hour or two had flown by. I particularly liked taking calls while in it. Now matter how much a waste of time the call was I would get a couple of kilometres in. I eventually was up to 10 milles a day. 4 km per hour for 4 hours. I had days when I walked more but I think 4 hours a day is a good limit point for me