Take MY dog for a walk. Sure, sure, you think taking your dog for a walk would be just as good, and I'm not saying it wouldn't help, but taking my dog is way better. I promise.
You won't just get a brisk 15 minute walk, you'll be required to stay outside, for a minimum of 30 minutes, and it won't just be walking. You'll have the pleasure of increasing stamina by chasing squirrels, birds, dogs and cyclists; increasing bicep strength by playing a random game of tug of war; and increasing heart rate by dealing with intolerant strangers after a tug of war the prize of which is said strangers. She will also force you to continue this shirade well into the depths of sub-zero winter.
She is for rent. Will consider adoption to a loving...er...tolerable home.