Why is my dog pacing anxiously?

Reasons a dog paces restlessly include: first, being kept indoors too long and feeling anxious; take it out regularly to burn energy and stabilize mood. Second, if it is used to going out to relieve itself and the owner forgets, it becomes restless from holding urine. Third, some dogs are very attached to their owners and become anxious, even developing separation anxiety, when left behind. Finally, a dog in physical discomfort often paces; if it shows abdominal pain, vomiting, or other abnormalities, see a vet promptly.