As a dog daycare operator and groomer for 30+ years, I have found that many clients feel that just daycare is more than enough exercise for their dog, and sometimes it is. However, large breed dogs need at least 30-45 minutes of good solid exercise a day. The best form of exercise for a dog is walking. This not only keeps a dog in good physical shape, but it also helps with behavior issues. I see dogs on a daily basis that are destructive in the home or have truly serious behavior problems that could be cured by a daily walk. Most of the aggressive behavior that I witness at times could also be completely fixed by that daily walk.
Walking your dog not only burns off excess energy, but helps you bond with your dog. You get a chance to become the leader in training your dog. It will help in setting boundaries that are so important for dog training. Your dog will more than likely meet other people and other dogs during your walk which will be a great chance to work on social skills. It will give you, the owner, a time to work on leash corrections. This, in turn, will lead to being more at ease with other dogs. New people too! The best behaved dogs…especially larger breeds,that I see, are the ones who get a daily walk.
A good link for dog walking info and training can be found at http://www.dogbreedinfo.com/articles/dogwalk.htm
Walking helps digestion as well, which builds a strong immune system. This is helpful in house breaking too. If your dog is on a schedule for relieving itself, it will have less or no accidents in your home.
So get out there and walk your dog. they will love you even more for it!!!