Not so much any more. The dog was a fine companion, he's built for speed and my labored, dinosaurian plodding was nothing but a brisk trot for him. He could go infinitely faster and far longer and still not be tired. Once he figured out not to dart in front of me to sniff something on the other side of me (thus spectacularly tripping me) we ran together just fine. I didn't make it far or fast before I was done.
Still, it's good for the dog and it's good for me, so I should keep doing it. Next time *before* dinner though, I think!