My first reaction is that sedentary refers to a lifestyle without much exercise rather than one without much travel. I notice from Google a number of references to travelling people (e.g. gypsies) using sedentary to refer to non-travelling communities, but that is a specialised context.
"Sedentary" is not a medical term. From the WR dictionary (did you look it up?):
sedentary: having or showing inactivity or lack of exercise
You can access the dictionary by entering a word or phrase in the search box at the top of the page. There are also many other English-language dictionaries online; enter the word in Google to find them.