Thermoregulation is the scientific term for maintaining the correct body temperature. Normal body temperature for dogs is 100-102 degrees.

Maintaining correct body temperature requires the body to have a steady balance between heat production and heat dissipation (removing heat from the body).

In dogs, the most important ways they remove heat from their bodies are convection (cool air moving across the skin, allowing heat from the dog to transfer to the air); radiation (release of heat into the environment through their pads); and evaporation (through panting).

Cool air moving across the skin is the most reliable method of heat removal in dogs. However, as the outside temperatures approach the dog’s body temperature, the system no longer works effectively and the dog begins to rely heavily on panting.

When normal body temperature can not be achieved heat stroke will set in. Dogs with excess weight become high risk for heat stroke because they have decreased ventilation capacities. Fat occupies a large amount of the area the lungs and diaphragm need to expand properly, and the fat creates excess insulation for the dog’s body (like a coat).

An overweight dog is predisposed to heatstroke, but it also increases their likelihood of death from a heatstroke event. A 2006 retrospective study evaluated mortality among a group of dogs diagnosed with heatstroke. In this study, they found obese dogs to be twice as likely to die as normal weight dogs. The study identified obesity as an independent risk factor for heatstroke related death.

Our interpretation of these findings further enforce the need to reduce the level of overweight and obese dogs in our care as Houston summers put them at far greater risk than other parts of the country.