Dogs' shortness of breath may be caused by hot weather or dreaming. Of course, there are also some dog breeds with short mouth and nose, most of which have rapid breathing and exhalation when sleeping, such as dogs such as pugs and foxes, which are all normal physiological conditions.
In addition to the above normal phenomena, if a dog catches a cold or suffers from a heart and lung disease, it will also experience shortness of breath when sleeping. The owner needs to carefully observe the dog's condition. If there are abnormal manifestations, such as abnormal gum color, abnormal color of the conjunctiva on the medial eye, etc., you should take the dog to the pet hospital for examination in time to clarify the cause.
In addition, some dogs have flat faces and short nasal structures, so their breathing will be more rapid when sleeping. For example, dogs such as Pak and Faldog have a very heavy breathing sound.