[Maximo]

I'm sorry your baby is experiencing this. Have the vets ruled out collapsed trachea? Heart sounds okay?

Whatever the cause may be, keeping your dog slim is important. If your dog has any extra weight, this will make breathing problems worse.

You are doing the right thing monitoring his activity to keep him from over exerting himself. Keep him cool too. Dogs have higher body temperatures than humans. Try to minimize anything that would be an allergen indoors and outdoors, dust for instance.

I'm sure people with more experience will give your some more advice on how to help him.