Okay, now you’ve done it Ben. 
I’ve had a treadmill desk for about six years, but… I’d fallen out of the habit of actually walking very much, mostly using it as standing desk. About a month into the pandemic, I realized that some days I was walking only a few hundred steps total. So, I got myself a new Fitbit and resolved to actually walk.
If you’re doing a standing desk already, I really really recommend this. It’s actually easier than standing for long periods of time. When standing, I tend to want to lean and slouch, and, yeah, feet get tired. With walking, even at 1-2 mph, this doesn’t happen.
Plus, I get automatic exercise, which is a key because of my other pandemic behavior of stress-eating and drinking. (I think this may be the only ADHD-friendly form of exercise… with exercises where I have to do something, it’s not the activity or strain that kills me, it’s the getting bored before getting to ten reps.)