Dogs can only cool themselves off by panting and by sweating through the pads in their paws.

Dogs only perspire around their paws, which is not enough to cool their bodies down.

To rid themselves of excess heat, they pant. Air moves through their nasal passages, which pick up excess heat from the body. As it is expelled through the mouths, the extra heat leaves along with it. Although this is a very efficient way to control body heat, it is severely limited in areas of high humidity or when the animal is in close quarters (like a car).

The shape of a dog’s nasal passage can contribute to the dog’s tendency to overheat. Brachiocephalic (pug-nosed) dogs are more prone to heatstroke because their nasal passages are smaller and it’s more difficult for them to circulate sufficient air for cooling.

Overweight dogs are also more prone to overheating because their extra layers of fat act as insulation, which traps heat in their bodies and restricts their breathing capabilities.

Age can also be a factor in an dog’s tendency to overheat — very young dogs may not have a fully developed temperature regulating system, and older dog’s organ systems may not be functioning at 100%t, leaving them prone to heat-related damage.