Heat Stroke: A (Really) Hot Topic

by Rick Marrinson, DVM, Longwood Veterinary Clinic


Anyone who has spent time outdoors in mid-summer or lingered in a closed car on a warm day will appreciate what it feels like to overheat.


Magnify that effect to a temperature at which the brain begins to cook and vital organs fail and you begin to appreciate what a heat stroke would feel like.


Heat stroke, or hyperthermia, occurs when body temperature exceeds a physiologically tolerable level and damages internal tissues including the nervous system, the heart, liver, and kidneys. For dogs, whose normal body temperature is between 100° and 102.5°F, heatstroke can occur at body temperatures that exceed 106°F for greater than 20 minutes.

Due to their anatomy and physiology, dogs are particularly susceptible to hyperthermia. First, dogs are covered with hair which holds in body heat. Second, dogs do not sweat which further inhibits their ability to cool themselves. If allowed to be overactive on a warm day, or if left in a closed vehicle for even short periods on moderately warm days, dogs’ body temperatures can reach dangerous levels in as little as fifteen minutes.


Symptoms of heatstroke include:

  • heavy panting

  • weakness

  • mental depression

  • vomiting

  • diarrhea


If your dog exhibits these symptoms, the best emergency treatment is to wet them down with cool (not cold) water. Do not submerge in ice water or apply ice directly to the skin.


After initiating the cooling process, and even if your dog appears to be responding, proceed immediately to a veterinarian for continued care. Many of the severe, life threatening symptoms of heat stoke are delayed and if heat stroke victims do not receive appropriate care, they are acutely at risk of death.


Sadly, most episodes of heat stroke are entirely avoidable with a bit of common sense. Do not exercise your dog during the hottest times of day, make sure there is plenty of drinking water available, and never, ever leave your dog for any length of time, on any day, in a closed vehicle.