Something serious, that’s for sure! Heat (panting) is often a sign of infection. Panting can be a sign of pain. When dogs come to see me with this complaint, we look at their chest – for infection – either bacterial or fungal, and the rest of their body for pain. This diagnostic workup means chest x-rays (radiographs), perhaps hip and spinal xrays, and bloodwork. What is interesting is, depending on where you live, dogs can have fungal pneumonia, and you don’t even know it but for a subtle change like panting at night. Occasionally, this panting is a sign of heart enlargement – this will be found with the chest x-ray. Regardless, keeping you up, meaning keeping himself up, which means your pup needs a trip to the veterinarian.