Warning Signs Your Dog Is Suffering from Heat Stroke—and What to Do About It

Updated: Jan. 12, 2024

Heat stroke in dogs can be deadly if left untreated. Here are the warning signs to look out for—and how you can prevent it from happening.

Summer is a season filled with abundant sunshine and warm temperatures, creating the perfect conditions for outdoor activities galore. Dog parents, in particular, love getting their fur babies outside in the warmer months to enjoy rolling in the grass, playing fetch and other dog-friendly activities. However, parents of these four-legged companions need to know the risks of bringing dogs out in the heat. One of the biggest risks to keep in mind? Heat stroke in dogs.

“Heat stroke is not always obvious and can be life-threatening if not addressed promptly,” says Mondrian Contreras, DVM, a veterinary expert with Pumpkin Pet Insurance. That’s why it’s crucial to monitor your dog’s behavior, regularly check for signs of illness and be aware of the dog dangers in your own backyard—which, yes, includes the sun. It’s also important to know the symptoms of heat stroke in dogs so you can identify the issue right away and treat it. If you don’t know what to look for, don’t worry; we consulted doggy experts to learn about heat stroke in dogs, how to spot it and the summer safety tips that can prevent it from happening.

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What is heat stroke in dogs?

Heat stroke occurs when a dog’s body temperature is above 105 degrees after they have been exposed to high heat, without previous signs of illness. Normally, a dog’s body temperature falls between 100.5 and 102.5 degrees, and it’s considered “elevated” once it hits 103 degrees.

Now, it’s worth noting that their body temperature rises when they’re fighting off an illness or infection, similar to humans, but there’s a difference between a dog that has a fever and a dog that’s suffering from heat stroke. If a dog’s temperature hits that 105-degree mark after they’ve been exposed to heat and weren’t sick beforehand, they’re entering heat-stroke territory.

What causes heat stroke in dogs?

Heat stroke in dogs happens when pups can’t cool themselves down after becoming too hot. When humans are hot, we sweat to regulate our body temperature, but dogs can’t sweat the way we can. While humans sweat pretty much anywhere on their bodies, dogs only sweat through their paw pads and nose. That small sweat space doesn’t do much service for hot canines, which is why they also pant to expel excess heat and cool down.

But sometimes panting and sweating just don’t cut it—especially when dogs are exposed to hot temperatures. Their organs can become severely damaged if they can’t properly regulate their body temperature, which is why heat stroke can be fatal if it’s not addressed quickly.

Dr. Contreras says there are several situations that can lead to heat stroke in pups, but some of the most common ones include:

  • Leaving a dog in a car on a hot day
  • Leaving a dog outside without water or proper shade
  • Exercising a dog that is predisposed to developing heat stroke on a hot day; predisposing factors may include brachycephaly, obesity, tracheal collapse (a narrowing windpipe) and arthritis

What makes a dog more susceptible to heat stroke?

Technically speaking, all dogs are susceptible to heat stroke—but some dogs do have a higher risk of developing it. According to Zach Lovatt, a research fellow on animal behavior and an expert in pet care, short-headed and short-muzzled dogs, overweight pups, dogs with cardiac issues and very young or very old dogs fall in the more vulnerable category. Dogs with thick, dark coats could also have a higher risk of overheating.

Which dog breeds are more likely to suffer from heat stroke?

Dr. Contreras says brachycephalic breeds (aka flat-faced dog breeds) have a higher risk of suffering from heat stroke due to their anatomy. “Their shorter, narrower nares, elongated soft palate and a smaller-diameter trachea all make breathing more difficult, ” he explains. These breeds include:

  • French and English Bulldog
  • Boston Terrier
  • Pug
  • Bull Mastiff
  • Boxer
  • Pekingese
  • Chinese Shar-Pei
  • Chow Chow
  • Lhasa Apso
  • Shih Tzu

While Dr. Contreras says he’s seen heat stroke most often in Bulldogs, French Bulldogs, Pugs, Chow Chows and French Mastiffs, he’s seen it in non-flat-faced breeds as well, including Greyhounds and Golden Retrievers.

What are the signs of heat stroke in a dog?

Smiling three-legged Boxer mix at a dog park. - The Amanda Collectionamandafoundation.org/Getty Images

Signs of heat stroke in dogs include:

  • Excessive panting
  • Gum discoloration
  • Dry gums
  • Excessive drooling
  • Thick drool
  • Increased heart rate
  • Muscle tremors
  • Gastrointestinal upset, including vomiting, diarrhea and black tarry stool
  • Disorientation
  • Lethargy
  • Prolonged loss of appetite

How do you treat heat stroke in dogs?

If you suspect your dog is suffering from heat stroke, Dr. Contreras advises you to take them to the vet immediately for treatment. However, there are actions that can help your canine right away, including:

  • Getting your dog into a cool and shaded area
  • Wetting your dog with cool (not cold) water; if the water is too cold, it could send them into shock
  • Giving your dog small amounts of cool water to drink

One thing Lovatt says not to do in this situation: shave your dog’s fur. Your pup’s fur actually acts as an insulator, keeping them cool in the summer and warm in the winter, so getting rid of it will throw off their natural body regulation process.

Once you get to the vet, Dr. Contreras says the staff can cool your dog down by pouring water on them and putting them in front of a fan to create convective cooling. Staff can also use IV fluids, a light sedative and oxygen to help with heat stroke, in addition to wrapping your pup in ice packs to gradually lower their temperature.

How do you prevent heat stroke in dogs?

You can prevent your dog from developing heat stroke by doing the following:

  • Never leave your dog alone in your car or outside.
  • Avoid exercising your dog during the hottest time of the day; instead, exercise them in the early morning or late evening, when it tends to be cooler.
  • Keep your dog inside on extremely hot and humid days; limit your dog’s outdoor activity when the temperature is above 80 degrees and humidity is above 70%.
  • Always have water available for your dog; if you’re on the go with them a lot, consider getting a portable dog water bottle to keep them hydrated.
  • Understand your dog’s breed risks or other predisposing factors that could put them at a higher risk for heat stroke.
  • Pay close attention to your pup at the dog park; dogs can get extremely excited when playing with other dogs and overheat if left unattended.

Dogs deserve to enjoy the nice summer weather, and they can safely do so with the help of their humans. Knowing the risks associated with heat stroke and the warning signs it’s happening to your dog will help Fido lead a healthier, happier life in the warmer months.

Now, grab your pup’s favorite toy and head outside to enjoy the sunshine responsibly!

About the experts

  • Mondrian Contreras, DVM, is a veterinary expert with Pumpkin Pet Insurance. He also owns Carol Stream Animal Hospital in Illinois and is the founder of the VetBros Pet Education Charitable Fund, which helps pets in need of lifesaving procedures.
  • Zach Lovatt is the founder of The Pampered Pup, a website dedicated to dog care and dog wellness. He is also a research fellow on animal behavior, a pet advocate and an expert in pet care and everything pet-related.