Heatstroke in Dogs: What Happens In The Dog’s Body with Heatstroke?

Every summer, veterinarians warn about the dangers of excessive heat for dogs. Why is heatstroke so dangerous?

Heatstroke in Dogs: What Happens In The Dog's Body with Heatstroke?

Heatstroke is characterized by a body temperature between 106 and 109°F (normal is 101.5°F give or take a degree). It is most likely to develop under one or more of the following conditions:

  • hot and humid weather combined with exercise and/or a lack of shade and access to water
  • being confined in a car or other location where heat can build up
  • obesity
  • advanced age
  • heart disease
  • upper respiratory disease (e.g., laryngeal paralysis or brachycephalic airway syndrome)

But what exactly happens when a dog’s body temperature reaches 106°F or above, and why is it so dangerous?

First, as a dog’s temperature begins to climb, the body cools itself via:

  • panting
  • drooling, and
  • dilating blood vessels on the surface of the body (vasodilation)

These mechanisms are sufficient up to a point. However, if there is no relief from high external temperatures, the dog’s excessive panting, drooling and vasodilation leads to dehydration and low blood pressure.

These conditions inhibit the body’s ability to cool itself. It sets up a vicious cycle wherein the hotter the body becomes, the less effective are its mechanisms to deal with the situation.

When body temperatures reach the danger zone:

  • proteins break down
  • cell membranes are damaged, and
  • the body can no longer produce energy at the cellular level

As tissues degrade and blood clotting abnormalities develop, the kidneys and liver begin to fail, the lining of the gastrointestinal tract dies, and heart and brain damage occur.

If a body temperature of 110°F is reached, a dog can die within just a few minutes.

Early symptoms of heatstroke include

  • extreme panting
  • a rapid heartbeat
  • red mucous membranes
  • vomiting, and
  • diarrhea

As his condition worsens, a dog may suffer from:

  • difficulty breathing
  • abnormal bruising
  • bloody vomit and diarrhea
  • blue or pale mucous membranes
  • collapse
  • seizures, and paradoxically
  • a lower than normal body temperature

First aid

If you suspect that a dog is suffering from heatstroke, thoroughly soak him with cool water (do not use ice though) and transport him to the nearest veterinary clinic in a car with the air conditioning on or with all the windows open.

Heatstroke has a mortality rate of around 50%, but with prompt and intensive treatment, many dogs can survive!

Related articles:
Signs, Symptoms And Treatment Of Heatstroke In Dogs
Symptoms To Watch For In Your Dog: Excessive Panting

8 Comments
  1. Reading what happens when a dog overheats, I realise that it is very dangerous, so thank you for this timely reminder during the American and European summer months. Wow they can go downhill fast – I m just glad there is action you can take..

    I remember a veterinarian did a youtube video about what happens in a car to a dog on a sunny day. He sat in the car and reported as it got hotter and hotter. It was frightening to see.

  2. I was very worried about my daughter, her wife, and their dog, last week. They live in an apartment in Seattle and it was over 104 degrees. Thankfully, they are okay, but I know a lot of pets and humans were not.

    • Yes, unfortunately, it can get so hot that one might be in danger even at home. We used to live in a horrible apartment like that–we were walking around wet, that actually helps.

  3. I always worry about Layla and heat stroke that is why on hot days if she is out I make sure she has a cooling vest on her which keeps her temperature cool as they stay damp and cold for about 4 hours. If we are in a park I make sure there is shade and lots of water.

  4. Heat stroke is something we think about quite frequently after spending time in Arizona. It’s amazing how many people do not understand how hot a car can get (even on what may feel like a cool day) – and how quickly a dog can fail in a warm car. Great reminder and I will help get the word out by sharing it!

  5. Heatstroke is so scary! We recently moved to Florida and we love long walks with our Husky, Icy. I worry a lot about her overheating, especially in Summer. We cut our dog walks timing from our usual 40 minutes to around 20. If it’s excessive, we’ll skip the walk and play puzzle games indoors. It is very difficult to spot when the dogs are getting overheated – it’s easier at home because they will go to the door when it’s too hot for them. We just have to watch them really carefully when it’s very sunny & hot.
    Love & Biscuits,
    Dogs Luv Us and We Luv Them

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