Puppies are far better behaved when they get plenty of exercise and enrichment, but you must take care not to over-exercise a young puppy. A good rule of thumb is to give a puppy no more than 5 minutes of exercise for each month of age, two times a day. So an 8-week-old puppy (2 months) should get 10 minutes of exercise twice a day. Obviously, there are breed differences which may make a difference in these recommendations. A Border Collie may need more opportunity for exercise than an English Bulldog. Purina shares some excellent information on "How to Exercise Your Puppy”.
Enrichment is a different but equally important part of your puppy’s development. Canine enrichment uses a range of activities that are designed to challenge and exercise your puppy’s brain. These exercises are as important as physical exercise and can significantly reduce destructive behaviors by replacing them with something acceptable. The ASPA offers inexpensive ways to offer at-home enrichment for your puppy and Rover.com discusses different types of enrichment exercises and suggests specific activities.