I just came across an article that mentions that ~1.4 miles per hour on a treadmill desk is the “optimal” speed for beneficial effects on memory and attention. (I go over it HERE). I also saw another article that says (if you don’t plan on exercising at all otherwise) that walking for ~40 miles a week is the optimal amount for cardiovascular health. This tells me that for the optimal health and memory effects of using a treadmill desk, I should be using it for about 4 hours every day walking at a pace of 1.4 miles per hour. If I can do that, then I apparently won’t gain any additional cardiovascular or memory benefits. There are lots of confounding factors and caveats (I mention many of them in my analysis of these articles, linked to above.) But I think this kind of gives a general number and range to shoot for.