I run with my Corgi, doing what I call "Project SuperCorgi." He has never been fat, but I did a lot of research on the breed before I bought him and learned that the *only* health defects that can affect a well-bred Corgi stem from letting them get overweight. In other words, joint problems. With his long-term health in mind, I began running him as soon as I felt he was old enough to do anything more vigorous than the dog park. At 9 months I started him off at 3 miles.
Now, at 20 months, I have him running 3 miles on Thursdays, 8-9 miles on Fridays and 5 miles on Sundays on a very hilly trail. I've got him up to 6mph on the Wed/Fri runs. His coat is slick and shiny, and he is trim and buff. Playing tug-o-war with him is like doing a rowing machine on high resistance. The vet always remarks on how good his health is. I am hoping to run him for most of his life, so that he will never get hip or back pain. The only "people" food we give him is the occasional bite of fruit or lamb on Fridays, when he has run long-distance. Not only is he healthy, but he is one of the happiest dogs I've ever seen. He's always grinning. When we run, if he starts to get a little too hot or tired, I slow to a walk for a minute or two. When he's able to run again, he looks up at me and grins, very pointedly, to tell me he's ready. After we get home, he crawls into my lap and roll around. Then he falls asleep wedged between my husband and I as we watch tv after dinner.
People who do not exercise their dogs are not only missing out, but they are doing something very cruel. Even if all the dog needs is a walk, some people can't even be bothered doing that. I see a lot of very fat Corgis, basset hounds, labs, and golden retrievers, and I think, "Don't those owners realize they are sentencing their dog to likely depression, joint pain and early death?" People should not go without exercise, and neither should dogs. They get bored just like we do, and they want to see new places, smell new smells. And they want to exercise with you--whether it's running or walking. They look at it like it's a job for them to do. Even if it doesn't seem important, dogs need "jobs" because they want to please us. We owe it to ourselves, and our dogs, to exercise with them and deepen the bond between us, and to make sure we both live to our fullest.