Heat Exhaustion in Dogs and Cats

Heat exhaustion is a life-threatening condition that occurs in animals of all kinds. It is also called heat stress, heat stroke and hyperpyrexia. In the clinic, I see it most often in dogs. When dogs and cats are not able to dissipate heat, their body temperature soars well above the normal range of 100 to 102.5 degrees Fahrenheit. If the body temperature rises over 105.5, the internal organs are injured.  Kidney failure, liver disease, clotting problems, bloody diarrhea, vomiting, gastric ulceration, seizures and coma are a few of the conditions that may occur. Even with aggressive treatment, the prognosis is poor.

In my experience, heat stroke occurs most often when animals with problems cooling themselves are exposed to excessive heat and/or humidity. Here is a list of the health factors associated with heat exhaustion:

  1. Obesity
  2. Brachiocephalic breeds (The short and broad head is often associated with narrowed nostrils, elongated soft pallets and narrowed windpipes making it difficult to breathe.)  – In dogs this includes bulldogs of all varieties, Shih Tzu, Lhasa apsos, Boxers, Pugs and Pekinese. In cats, Persians and Himalayans are brachiocephalic. Some of these breeds like boxers and mastiffs are also heavily muscled which compounds the problem.
  3. Laryngeal paralysis
  4. Heavy coated breeds – Long hair cats especially Maine coon cats, Siberian huskies, Samoyeds,  Malamutes, etc

Environmental factors also play a huge role in causing heat exhaustion. Every summer, I am saddened to hear of children and pets who died after being left in a car. In climates with extreme temperatures including Las Vegas and Phoenix, leaving a pet outside can kill them. Recently, the evening news reported the death of a Labrador retriever who was left on an apartment balcony. I have seen animals develop heat stroke from the blowers used after grooming. High humidity is also lethal because panting isn’t as effective.

If you live with a pet prone to heat stroke, please keep them out of the heat.  I have seen heat stroke develop in as little as five minutes in geriatric pets who went outside and then couldn’t get back in the doggy door.  Watch for rapid respirations, a depressed attitude and dark red gums.  They may also experience vomiting and diarrhea.  If the dog is not cooled off quickly, their condition rapidly deteriorates into bloody vomiting, collapse, bloody diarrhea, seizures and problems breathing.  When the gum color changes into a sick, pale gray I know death is coming.

To prevent heat stroke, keep your pet at a healthy weight.  Take walks and play ball early in the morning when temperatures are mild.  Limit their time outdoors during the heat of the day to a quick trip to urinate and/or defecate in the shade.  Then, return to air conditioning.  Last, watch their tongues closely for a change in color.  If their normal pink color deepens to purple or lilac, it is time to get indoors.  I know we all like to have our pets with us to soccer and baseball games, but sometimes the safest and most loving thing to do is leave them home.  They can help you celebrate after the event!



Shell, L. “Heat Prostration”, Associate Database – VIN, last updated 8/11/2007.

Published by kristennelsondvm

Dr. Kristen Nelson grew up on a farm in Watertown, Minn., where she developed a deep love for animals of all kinds. She received a Doctor of Veterinary Medicine degree from the University of Minnesota, College of Veterinary Medicine. Kris then completed a small-animal internship at the prestigious Animal Medical Center in New York City. In addition to writing and speaking, she cares for small and exotic animals in Scottsdale, Az. Dr. Nelson is widely quoted in the media. Her credits include Ladies’ Home Journal, USA TODAY, the Los Angeles Times and numerous radio and television interviews. Dr. Nelson has written two books, Coated With Fur: A Vet’s Life and Coated With Fur: A Blind Cat’s Love. Kris and her husband Steve share their home with rescued cats, birds and a dog.