My dog just started breathing really heavy and I'm not sure if this is normal. It just seems like he's having to put in a lot of effort to breath normally. How can we distinguish between regular panting or an illness?
As stated in the first answer, it is a normal reaction when they are hot or being active. However a dog breathing heavy or panting for no apparent reason can be a sign that the dog is stressed or anxious. Try stroking the dog and making him/her feel comfortable in their environment.
It’s normal for dogs to pant, especially when they’re hot, excited, or energetic. Heavy panting is different, though, and may be a sign your dog is dangerously overheated, coping with a chronic health problem, or has experienced a life-threatening trauma.
A pant is normal but serious heavy breathing other than panting can have a few different underlying causes that I would recommend getting your dogs breathing on video and going into the vet with that. From there the vet will work out a plan with you and let you know what is going on.