What is Heat Stroke in Dogs?

Heat stroke is a potentially life threatening condition that occurs when your dog’s core body temperature rises to a dangerously high level due to excessive environmental temperatures and/or the lack of opportunity to effectively cool themselves down.

Many online sources incorrectly simplify matters by stating that heat stroke in dogs is simply a temperature above 104°F (40°C), and such sources will often also use the terms “heat stroke” and “hyperthermia” interchangeably. These sources don’t actually provide the full picture, and here’s why:

Hyperthermia is just a fancy way of describing a core body temperature which is too high. However, this isn’t always due to heat stroke; bacterial and viral infections can also cause your dog’s body temperature to become very high, and in this case providing home care or veterinary treatment for heat stroke would be the entirely wrong plan for the patient! So, it’s clearly an important distinction to make!

Before we move on, let’s summarize those key points:
  • Hyperthermia in dogs is a body temperature which is too high,
  • Hyperthermia can be caused by heat stroke or by infections.
  • Symptoms and Signs of Heat Stroke in Dogs

    So, how do you know if your dog has heat stroke?
    Early signs to be vigilant for include:

  • Panting
  • Searching for a cool place to rest, such as shade
  • Lying down in a spread out body position
  • Loss of interest in eating

  • If your dog is unable to cool down, heat stroke may progress, resulting in more severe signs:

  • Bright red gums
  • Diarrhea, which may be bloody
  • Collapse
  • Seizure
  • Small red or purple spots (called ‘petechiae’) on the skin or gums
  • Difficulty breathing
  • Extreme lethargy , and/or
  • Confusion
  • Heat Stroke and Dehydration in Dogs

    Heat stroke often goes hand-in-hand with dehydration in dogs. Medically speaking when we say “dehydration”, we mean that water losses have exceeded your dog’s ability to keep their fluids topped up, resulting in low total body water (both inside the blood vessels, and within the cells of the body). Every pet owner should be aware of the signs of dehydration in dogs.

    Mild dehydration doesn’t have any visible signs, so you won’t be able to notice it, other than the fact that your dog may seem thirstier than usual.

    Moderate dehydration occurs once your dog has lost between 5-9% of their body’s normal total water volume. At this point, you’ll notice that:

  • Your dog’s gums feel dry and tacky to the touch
  • Your pet’s energy levels are reduced
  • Their skin is becoming increasingly less elastic (and springs back less easily if you pull their scruff up into a tent)
  • When you press on your dog’s gums so that they blanch to white, they take longer than usual to return to pink. In a well hydrated dog, this capillary refill time (or CRT) is less than two seconds, rising to 2 seconds with moderate dehydration.

  • If the situation is allowed to progress to one of severe dehydration, your dog will develop:

  • A very prolonged CRT of 2+ seconds
  • Eyes that appear sunken
  • Skin that doesn’t spring back when tented
  • Extreme lethargy; your pet may even become unresponsive

  • Severe dehydration can be fatal within hours, as cardiovascular shock occurs due to insufficient volume of fluid being present within the blood vessels. For this reason it must be rapidly addressed with intravenous fluid therapy under the intensive care of a veterinarian.

    Prevention of Heat Stroke in Dogs

    The good news is that heat stroke is an entirely preventable problem. Following precautionary measures - especially in summer - will help protect your pet from the effects of this perilous predicament.

  • Check the temperature before exercising your dog. Some dogs - especially those who are overweight flat-faced, puppies or those with thick coats - may experience heat stroke during exercise even at relatively low temperatures of 70-75°F (21-24°C).
  • Ensure your pet always has access to a cool, shaded and well-ventilated location where they can rest.
  • Never let your dog’s water supply run dry.
  • Consider providing your pet with a fan; the movement of air over your pup’s body will really help them to cool down effectively.
  • If travelling with your pet in an Car & RV, constantly monitor the internal temperature and humidity in real-time with the Waggle Pet Monitor, which will promptly notify you of changes, allowing you to make sure your four-legged friend stays cool, comfortable and (most importantly) safe.

  • Temperature monitors are a fantastic way of helping to keep your pet safe in summer. Owners should ensure such devices are correctly fitted and maintained according to manufacturer guidelines, and remember that every electronic device - however well designed and built - has the potential to fail in rare circumstances.

    First Aid for Heatstroke in Dogs

    Whether on the road, in the dog park or at home, if you notice signs that your pet is overheating it’s crucial not to delay acting. It’s recommended to prioritize cooling your dog down even above transporting them to the vets, although you should also call your local vet clinic for advice at the same time as starting first aid cooling measures.

    At the first sign of heatstroke, immediately move your dog to somewhere cool (but not cold). Provide good ventilation and airflow, for example using a fan. Offer your pet fresh, cool water but do not try and force them to drink.

    If it’s possible to do so, you should also pour cool (but not cold) water over your dog, avoiding their head. Do not place wet towels over your dog’s body: this was once recommended as a first aid measure for heat stroke, until it was discovered that the towels would actually rapidly warm up and then begin to trap heat and make matters worse rather than better.

    You’ll also need to transport your dog as soon as possible to your nearest veterinary hospital, where they will be admitted for stabilization if your vet confirms the diagnosis of heat stroke.


    Which dog breeds are most prone to heat stroke?

    Brachycephalic (flat-faced) dog breeds such as Bulldogs, Pugs, Boston terriers and Shih Tzus are extremely prone to heat stroke, even on relatively mild summer days. Dog breeds that thrive in the cold such as Huskies and Malamutes are also more prone to heat stroke, as are large dogs (>15kg) and those who are overweight.

    Is heat stroke in puppies worse than in adult dogs?

    Heat stroke has the potential to be an extremely serious condition for all dogs, yet puppies are at greater risk of developing severe heat stroke because their temperature regulatory mechanisms are not yet fully developed meaning their built-in “cool down” systems are less able to kick in quickly.

    How can I help keep my dog cool during road trips?

    Help keep your dog cool during road trips by travelling with them in an airconditioned vehicle (ideally), or as a minimum safety measure ensure that ventilation and a breeze and provided and that the vehicle’s internal temperature is constantly monitored. You can use the Waggle Pet Monitor effectively for this purpose.

    Waggle Pet Monitor

    The best way to keep your pet safe whilst travelling in an RV is to never leave them unobserved and to be extremely vigilant for the early signs of heat stroke, but in reality there are many reasons why we might need to briefly step away. There might also be occasions where it’s safest for your pet to travel in the back of your RV whilst you ride up front.

    If you can’t see your dog, as a minimum safety measure you should have a temperature and humidity monitor installed that will alert you within seconds if your pet is in danger (such as the Waggle Pet Monitor). You should take care to ensure this is correctly installed and that the settings are appropriate for your dog and their individual heat and humidity tolerance. If in doubt, err on the side of extreme caution!

    Another valuable safety advantage of the Waggle Pet Monitor is that it will alert you instantly if your RV loses power, allowing you to return immediately to address a situation in which your aircon may have cut out. Waggle provides real-time temperature and humidity updates, which can also be used to keep friends and family informed if your pet is at risk, so that help can be summoned without delay in the case of an emergency.

    Don’t start your summer vacation without pet temperature monitor.