The changes your dog goes through as he ages are natural and are, in fact, very similar to those same changes we, as humans, experience. For instance, with aging, a dog's activity level slows. Without mental stimulation to keep him sharp, an aging dog may become slow and lethargic and his appetite may change.

Older dogs may begin to have accidents in the house with little or no warning, and for no known medical reason. An older dog's sleep cycle changes too, and he may begin to sleep more during the day and less at night. As your dog ages, expect his interaction with you (and other family members) to begin to diminish -- he'll greet you less enthusiastically (or not at all); he'll follow you less (if at all); and he'll rarely seek your attention.

Your dog's mobility becomes reduced as he ages. Plus, he may become more aggressive.

Don't be surprised if your older dog appears confused or disoriented at times. Some older dogs may actually exhibit signs very similar to human Alzheimer's disease, and suffer short term memory loss, changes in behavior, and just a general slow-down in their thought process.

What can you do to help your aging dog? One place to start is your dog's diet. Check with your vet and make changes to your dog's diet according to his medical needs. Keep his weight down, too. Small, more frequent meals are best. Remember, an overweight dog has trouble with mobility, and this is only complicated with age.

Grooming your older dog is still important. Brush him frequently to help stimulate his circulation.

It's important that your dog is still getting enough exercise. You may need to adjust your walking schedule to include more frequent, shorter walks. And allow him to do his business after each meal, just before bedtime, and first thing in the morning to reduce accidents.

And just like you as you begin to age, provide your dog with a warm, comfortable place to sleep.

It's important to note that many aging symptoms are similar to symptoms of a sick dog, so be sure to have your dog examined by his veterinarian at least twice a year to rule out any illness.