I call them "Squirrel Sprints" because our intense bursts of chasing small creatures interspersed with slower strolling and sniffing is a form of interval training that actually has increased my speed. When we get to the high school, I'll tie Sheba's leash to the fence while I do sit-ups and push-ups at the par-course--a strengthening workout I'd often skipped when I used to run solo. Then we finish up with an all-out race home, where the winner--Sheba--gets the first drink of water.

Of course bringing a dog into your home is a serious responsibility not to be taken lightly. Unlike an expensive exercise machine, you can't stick a dog in a corner and use it as a clothes hanger when you get tired of it.

But in addition to being a fun way to activate your whole family, having a dog also provides some simple--but profound--lessons in leading a healthy life. Here, for example, are some health secrets I've learned from exercising with Sheba:

1. Greet everyone you meet, but keep your ears cocked until you determine if it's friend or foe.

2. Lap up water at every opportunity.

3. Enjoy nature in all her moods. Walking in the rain or snow can be delightful. (Only a crazy human, however, would run in summer's mid-day heat.)

4. Stretch frequently, especially when you've been sitting or lying down. The yoga pose called "Down Dog," which is modeled after a canine's favorite "paws forward, tail up" stretch, is an unparallelled way to remove kinks from the legs, back and shoulders.