there is not set or even rule of thumb guide. it depends on the dog an his fitness level. a health pup in relative good fitness should have no trouble with a mile. Then again another factor is how fast. A 10 minute mile jog would hard/impossible for the but but a 20 to 30 minute mile should be OK Also the terrain is a factor. A well worn path is going to be easier for a pup with short legs to keep up than one with a lot of obstacles to negotiate.
http://www.flyingdogpress.com/fitness.html
Exercise has benefits for dogs too! Some simple ideas for keeping your couch potato in reasonable shape.