Allow the dog to catch its breath and calm down. After the dog has recovered you may be able to continue the activity at a slower pace.
[header] How to tell if your older dog is over exerting itself [title] Look for excessive panting and trouble breathing. [step] If your dog is getting winded more easily than it used to then you may need to exercise it less. Problems breathing, coughing or hacking, or lots of panting can be a sign that your older dog is doing too much.