One of the joys of owning a dog is the opportunity to play with it. And one of the advantages of playing with your dog is that it's great exercise. Regular exercise is an important part of maintaining your pet's health. Puppies play constantly, which provides them with most of the exercise they need. An older dog needs exercise just as much, and a daily walk around the block probably isn't enough. You may not have enough energy to keep up with a playful pooch, so let him do most of the work. Have him fetch balls or Frisbees; the dog'll love it and you don't have to run all that much. Of course, if you already walk or jog, take your dog along. The exercise will be good for both of you.