To maintain a healthy Great Dane it should get at least 15-30 minutes of good exercise a day. This can be a walk, chasing a ball, jogging, hiking or other moderate exercise. The amount is dependant on the dogs age and general health. A puppy or young adult can handle more exercise than a 6 - 7 year old. However even an older Dane may be able to do more if it was kept fit & healthy as a young dog.