I had 2 back to back showings on my house last week and needed to get out for a bit with the dogs. I thought a quick walk around the dog park would kill enough time, so I loaded them up and we left. I literally walked 50 yards into the park, turned around and left. I spent the next 6 hours making sure my bulldog didn’t die. It was horrible. I wasn’t even outside for 15 minutes and this happened. I was completely blown away. Here is an explanation of heatstroke in dogs, the signs and what to do. I never thought it could happen to me until it did.

What Is Heat Stroke In Dogs?

When a dog’s body temperature rises over 104°F and his mechanisms for cooling himself off – such as panting – become overwhelmed and stop working properly, heat stroke sets in.

Sadly it’s not just a dog’s thermoregulatory (“cooling”) system that fails in heat stroke. As the condition progresses and the body temperature rockets even further above 104°F, most body systems fail. Amongst them are the all-important neurologic, urinary, circulatory, and blood clotting systems. Once these systems begin to fail, the likelihood of recovery from heat stroke is very slim.

While heat stroke can happen quickly, there is often a progression from mild heat stress to the more moderate heat exhaustion before reaching the most severe condition of heat stroke. Since prevention of heat stroke is crucially important, everybody should know and keep an eye out for the “early warning signs.” If you know these warning signs of heat stress and heat exhaustion you’ll be able to take appropriate steps before the situation progresses to a potentially deadly case of heat stroke.

Signs Of Heat Stress and Heat Exhaustion

Note that there are varying degrees of these signs, how obvious or severe they are, or even how many are noticeable at once, depending on the situation and how long the dog has been in the heat.

  • Moving more slowly than normal, not keeping up
  • Seeking shade and frequent rests
  • Seeking out puddles or other water sources for drinks
  • Persistent or prolonged panting
  • Loud or labored breathing
  • Rapid pulse
  • Dark red gums and tongue
  • Wide, stressed eyes
  • General increased anxiety
  • If in a parked car, these additional signs may be seen:
    • Barking
    • Pacing
    • Seeking out shady spots under the dash or seats
    • Clawing at the window, dash, or seats attempting to escape
    • Attempting to stick their nose or head out a cracked window
    • Slobbery nose or paw prints on the inside of the windows

Signs Of Heat Stroke

Again here, there are varying degrees and severities of these signs and not all will be present in every case. Also note that the signs listed below are in addition to the signs listed above for heat stress and heat exhaustion, and there is considerable overlap.

  • Vomiting – possibly including blood
  • Diarrhea – possibly containing blood
  • Drooling
  • Fast, thready pulse
  • Glazed over eyes
  • Staggering
  • Collapse
  • Unresponsiveness or apparently altered mental state
  • Seizures
  • Bruising of the skin or the gums – these small, pinpoint bruises, called “petechiae”, are often most visible inside the ears or on the underside of the belly

When Does Heat Stroke Happen?

When most people think of or hear about heat stroke in pets, they typically think about dogs left in hot cars. This is a good thing, as it’s certainly the most common cause of heat stroke. However, it’s important to recognize that hot cars aren’t the only place where pets suffer from heat stroke.

In cars and other vehicles
Multiple studies have shown how rapidly the temperature can rise in a parked car, even with the windows “cracked” and even on relatively mild days. These are numbers that everybody should be aware of and keep in mind when taking their pets (and kids) in the car.

  • In one study the average rate of temperature rise over the 16-day study period was shown to be a 19°F increase in just 10 minutes, 29°F in 20 minutes, 34°F rise in 30 minutes, and 43°F in 60 minutes. Anybody who has sat in a parked car on a warm day themself will appreciate just how uncomfortable any of those increases can be, and just how short a time 10 minutes actually is.
  • In the same study, on one of the (very mild) 72°F days, the temperature inside the car reached a dangerous 93°F in just 10 minutes! And it climbed from there to devastating and deadly levels quickly – reaching 105°F in 20 min., 110°F in 30 min., and 119°F in 1 hour!
  • Another study (also referenced below) showed that 80% of the temperature rise occurs within the first 30 minutes.
  • Two studies that specifically looked at the effect of leaving the windows cracked on the rate of heat rise in parked cars both found that cracking the windows does very little, if anything at all, to help prevent heat rise and overall risk for heat stroke.
    • One study showed a slight, but ultimately insignificant, decrease in the rate of heat rise from 6.25°F per 5 minutes (closed windows) versus 5.5°F per 5 minutes (windows cracked) over the first 20 minutes of the study. However, by the end of the 60-minute study period, the two cars reached the same internal temperature.
    • The other study found only a 2°F difference in final internal temperature between windows closed and windows cracked at the end of a 90-minute study period. And this was in spite of the fact that the vehicle with the windows cracked was (1) larger and (2) lighter in color… either of which could easily account for that minimal decrease in heat rise.

As you can see, when it’s hot outside heat stress can progress rapidly to a debilitating, and potentially fatal case of heat stroke for a dog left in a parked car for as little as 10 minutes. Even on a relatively mild 65-75°F day, 15-20 minutes of enclosure in a parked car can be enough to bring on a case of heat stroke in a dog. And this is true regardless of whether or not the windows are cracked.

During outdoor exercise, play, and even walks
Just like us, dogs generate heat when they play and exercise. Unlike us however, dogs aren’t covered with sweat glands to help them cool off efficiently and effectively. They mainly depend on panting to get rid of excessive heat. Combine that fact with the strong love of play and exercise that many dogs have – their “play drive” – and you’ve got a recipe for potential disaster on warm, hot, and/or humid days.

For dogs with certain medical conditions – including collapsing trachea, laryngeal paralysis, and even arthritis (see more at the article linked below) – even a short walk around the block during the warmer parts of the day can spell disaster.

Your dog counts on you to exercise caution and good judgment when taking him out for exercise and play on hot days.

During travel
Travel, be it by car, RV, plane, or another form, can put your dog at risk for suffering from heat stroke. The dangers are present both during the journey and even once you arrive at your destination. Be aware of these risks, book and plan your travel itinerary carefully, and recognize that your dog may need time to acclimate to the temperatures and humidity levels at your final destination.

When confined outside
Dogs who live outside and those who spend large amounts of time outside during warmer days are at avoidable risk of suffering from heat stroke, too. Reliable shade, plentiful water, and protection from hot asphalt and other surfaces are important to protect outdoor dogs. On hot days, please consider bringing your dog inside for his comfort. Depending on where you live, that might even be the law.