Dogs pant primarily to cool themselves down. Unlike humans where we have sweat glands all over the body, dogs have them only in their paws. These glands are called merocrine glands and help the animal to cool down. But the problem is that the surface area of dog’s paw is limited and they can’t cool themselves entirely based upon this.
To compensate upon this aspect, nature has provided dogs with one more powerful cooling mechanism i.e. panting. Dogs are covered with fur like coat all over their body and they tend to generate a lot of heat while playing or running around. So to just cool themselves down, they’ll stick their tongue out and start panting. During the process of panting, the tongue’s surface area increases considerably, which enables better cooling.
During the panting process, the cold air from outside is sucked in as a part of breathing mechanism and when it’s exhaled the thin water/saliva layer over the tongue evaporates making the cooling process highly effective. In fact, the air that is exhaled from a dog’s mouth while panting can be at the times 10 degrees warmer than the air that is exhaled from their nose.
One more important point to be noted in case of panting is that sometimes the heavy panting can by a signal of some illness that the dog might be suffering such as heatstroke or pneumonia. In such cases, an urgent veterinary visit is required and proper medical care needs to be taken care of. Sometimes dogs pant just to relax. As we human exercise or follow other methodologies to relax, dogs also do the same by panting, which releases stress-relieving endorphins and gives them the desired calm they require.
All in all in most of the cases when your dog pants, it’s normal and doesn’t requires any major attention. But sometimes when the heat is too much or the dog is heavily tired due to extensive playing or running then you may just give him a break so that he may be able to recover for the next round.