[header] How to treat heart failure in dogs [title] Restrict the amount of exercise your dog gets each day. [step] When a dog has a weak heart, exercise can add extra pressure to his condition. Heart failure can lead to difficulty with blood circulation, meaning that your dog's vital organs do not get enough oxygen. 
If your dog has heart failure, he should not be allowed to exercise heavily, though he can still wander around the yard. Forgo taking him on walks for peaceful hours petting him or letting him lounge.