Apparently the average radius of the Earth at its equator is 6,378,000m. This means that in a day, someone sitting on a couch at the equator would travel (2 * \pi * 6378,000)m, which equals 40053840m. There are around 86,400 seconds in a day, so the equatorial couch sitter travels at 464m/s (rounded to 3s.f). That’s 1040mph.

I think the average walking speed is 3pmh. Amusingly, the mph figure I calculated above is 1037 if rounded to 4s.f. rather than 3, so the speed difference between the walker and a couch sitter is literally a rounding error.

The conclusion here is something that everyone here already knew before I wrote this comment: it’s hard to make any sense of individual human health progress if we try to think of it on a planetary scale.