Last time I started a new project and worked on its architecture, I walked over 10km in a single day, according to my cellphone pedometer. In a tiny apartment! This trend lasted for a month, after which I sat down to actually implement this.
I thought it was just me being autistic but it's interesting to know others do it as well :)
I never worked in an office setting, but I can only imagine it would be extremely prejudicial to people like me and the author. Restraining us to a table would limit our output for the sole reason we would be unable to pace and think (no space and too much social pressure).
Anecdata: sometimes I visit my parents and work from their place. I can't pace there because I don't feel comfortable doing so, and that alone is enough for me to not be able to tackle challenging problems there.