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This is what happens to your dog when you leave it in a hot car

It can take mere minutes for a dog to suffer severe symptoms of heat stroke after being left in a vehicle on a hot day.
It can take mere minutes for a dog to suffer severe symptoms of heat stroke after being left in a vehicle on a hot day. BC SPCA

Though it’s well known that leaving a dog — or child — in a hot car could be fatal, each summer numerous stories surface about people having to break windows or call police to free a dog in a vehicle on a sweltering day.

Global News spoke with Shane Bateman, associate professor at the University of Guelph’s Ontario Veterinary College about what happens to a dog’s body when left in a vehicle on a hot summer day.

READ MORE: BC SPCA has received 151 calls of dogs in hot cars this May so far

“Dogs in particular develop heat stroke more quickly than most species,” explained Bateman. That’s because dogs, unlike most species, lack sweat glands that allow the skin and body to cool itself. Instead, dogs sweat through panting, a process that brings small amounts of air into lungs to aid it cooling its body.

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“It’s like an air conditioner that goes directly into the lungs,” Bateman said. And it’s in the lungs where half of the blood volume lies.

The optimal body temperature for a dog is around 38.5 C. It takes very little to begin the process of heat stroke and when that happens, it kicks off a cascade of events.

  1. Once the temperature inside a vehicle reaches 41 C — which, on a sunny day with temperatures rising to 25 C or more, can be just minutes — it prevents a dog from regulating its body temperature. The air is now extremely hot. The dog begins to pant, but instead of taking in cool air, it is now inhaling hot air into its lungs causing a rise in body temperature.
  2. Protein structures begin to fail, unable to do the work they were designed to do.
  3. The dog may begin to pant harder, which in turn speeds up the process.
  4. Blood vessels, specifically the lining, are exposed. One of the key functions of the lining is to keep blood in its liquid state. The damaged lining is unable to do that. The dog now develops blood clots in many different tissues.
  5. The heart, liver, kidney, gastrointestinal tract — all organs that are in constant need of oxygen and fresh fuel — begin to fail.
  6. The dog  may begin to vomit or have diarrhea.
  7. Brain is damaged. The dog now could have seizures or slip into a coma.
  8. Death

On a hot day with temperatures rising to about 30 C, this whole process can take anywhere between five to 10 minutes. And leaving a window open doesn’t make a difference.

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Bateman said that his team at the Ontario Veterinary College can see anywhere from five to 10 dogs each summer with extreme heat stroke. Of those, “The majority of them would pass away or be euthanized.

“Heat waves, are always frightgening days for us.”

On hot days reaching 30 C or more, it’s also important to cool your dog down on his or her regular walk. It takes time for the body to acclimatize to the extreme temperature, so spraying him or her down helps keep your best friend’s temperature regulated.

It’s important to cool down your dog on hot summer days.
It’s important to cool down your dog on hot summer days. AP Photo/Richard Vogel

Bateman said that many people who leave their dogs in their vehicles don’t have malicious intent: they’re usually unaware of how quickly the process can begin.

Signs that your dog may be experiencing heat stroke include the dog being dull and not as responsive as usual and bloodshot eyes. If the dog begins to vomit or experience diarrhea, it has reached a critical point.

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“Time is of the essence in these moments,” Bateman said. “Sometimes…even emergency life-saving therapy isn’t enough to turn the course.”

Bateman said that if someone finds a dog in a hot car, it’s important to get it emergency medical attention.

“Take a cool hose and spray the dog, and immediately get it into the coolest environment possible.”