CVMA | Documents | Heat Stroke Kills Silently and Swiftly

Heat Stroke Kills Silently and Swiftly

October 23, 2012

Heat stroke occurs when a pet's internal body temperature rises to levels high enough to lead to death. For heat stroke to occur, a combination of factors must come into play: a confined space, poor ventilation, and high ambient temperatures, such as that produced in direct sunlight.  Approximately 70 per cent of total body heat loss, in both dogs and man, occurs via the body surface.  As a result, continual air changes (i.e. good ventilation) in the immediate surrounding area of the body are essential in order to remain cool.  

In dogs, heat is also released through panting.  Heat lost in this way can contribute to an increase in the ambient temperature in an enclosed space. Lack of ventilation increases the temperature without allowing the body to effectively remove the excess heat.

Heat stroke has been known to occur in dogs that were in a confined space even though the room temperature was almost ten degrees centigrade below the dog's normal body temperature. Cats are better able to cope with high temperatures but only within reason. They can usually tolerate higher body temperatures because of their desert origins and their ability to cool themselves through licking.

There are a number of other factors besides ventilation that can increase a pet's chances of getting heat stroke. Such variables as the amount of sunshine, humidity, colour of car, type of seat covers, and wind factors all play some part. Health and weight of the pet, the thickness of the hair coat, availability of fresh water, recent feeding, and even a pet's own temperament can elevate body temperature. For example, a pet that is anxious, excited or frightened, or one that barks excessively, is more likely to get heat stroke than one that is calm or quiet. 

Brachycephalic breeds, such as Pugs, Pekes, Bulldogs, etc. are also more likely to have heat-related problems.  

Heat stroke occurs when a pet has an extremely high body temperature, usually more than 41 degrees C. (106-109 degrees F.).

Signs include:

  •  Rapid panting
  • Warm dry skin
  • Bright red gums
  • Vomiting
  • An anxious expression or staring

Collapse, coma and death follow shortly thereafter if the heat stroke is advanced. Even with proper therapy, some pets will die from multi-organ failure.

An animal with heat stroke must have its body temperature reduced as quickly as possible. Most effective is immediate immersion in a cold water bath. If unavailable, hosing it down with a garden hose, along with applications of ice packs, may be effective. The skin should be massaged vigorously, and the legs flexed frequently to encourage blood circulation. While this is being done, it is essential that the pet be transported to a veterinary hospital as quickly as possible.

Heat stroke can occur surprisingly fast, even when animals are left for only short periods of time in cars with the windows partially rolled down. Since prevention still remains the best alternative, animals are best not left alone in unattended cars or in a yard without shade and water in warm weather.