Minutes Matter

Protect your pet from heat stroke this summer

Each year SPCAs across Canada receive hundreds of reports of pets being left in hot cars. It takes mere minutes for a hot environment to become life-threatening for an animal. For dogs in particular, a rise in temperature can very quickly lead to a medical emergency. Humans have sweat glands, but our canine counterparts have very few and only on their paws, making it difficult or even impossible for dogs to regulate their body temperature in rapidly changing environments. 

Owner education is key as many people are not aware of how fast heat stroke can develop and the short amount of time it takes for a dog’s body to go into shock. The consequence of heat stroke can often be fatal. We sat down with OVC veterinary criticalist Dr. Shane Bateman to find out what heat stroke is and how owners can protect their pets this summer. 


What is heat stroke and how is it caused? 

Heat stroke is a term commonly used for hyperthermia or elevated body temperature and occurs when a pet can no longer cool down its own body. All warm-blooded animals that regulate their body temperature can be affected. A temperature above 103°F/39.4°C is considered abnormal; organ failure and death occur around 107°F-109°F (41.2°C-42.7°C). Heat stroke is much more common in dogs than cats, but can affect both species. The most common cause of heat stroke is leaving a dog in a car with insufficient ventilation. 

Why is heat stroke a medical emergency? 

Dogs cannot control their body temperature by sweating like people do since they only have a small number of sweat glands located in their footpads and their primary way of regulating body temperature is by panting. It often only takes minutes for a dog’s body temperature to rapidly increase. Flat-faced breeds of dogs such as pugs, boxers and bulldogs genetically have a restricted airway and are at greater risk for developing heat stroke. In these breeds, heat stroke can occur even when the outside temperature is only moderately elevated. Signs of heat stroke include panting and lethargy, difficulty breathing, vomiting, diarrhea, weakness or inability to stand and reduced responsiveness progressing to loss of consciousness and even seizures. Permanent organ damage and death is possible. 

What exactly happens to a dog’s body when they experience heat stroke? 

Hot conditions can prevent dogs from being able to regulate their own body temperature. It only takes minutes on a warm day for the air inside a car to become very hot. When dogs pant in a hot environment, they inhale that hot air directly into their lungs which causes their temperature to spike. When this occurs, protein structures in the body begin to fail. The linings of blood vessels are now damaged, which can cause blood clots in tissues throughout the body. Like humans, dogs require oxygen to their heart, liver, kidneys and more – these organs all start to fail from a lack of oxygen in the body, causing the dog to vomit or have diarrhea. The brain will then quickly become damaged, which may cause the dog to go into shock, produce seizures or even a coma, followed by death. 

Is heat stroke preventable? 

Yes, heat stroke is preventable! Each year during the spring, summer and fall, the OVC Companion Animal Hospital treats five to 10 pets with heat stroke. Unfortunately, sometimes the outcomes are tragic. Pet owners can prevent heat stroke by never allowing their animal to remain in a car that is not air conditioned, cool and running. Better yet – leave them at home; and avoid exercising their pet during the hottest times of the day. If you exercise with your pet outside, shift the time to cooler parts of the day such as early morning or late evening. On warmer days, resist the urge to go further than typical and actively reduce the amount of exercise on such days; ensure that pets have a cool or air-conditioned space in your home that they can escape to when needed. 

On the very hottest days, most people are aware enough to avoid the major risk factors. Unfortunately, pet owners sometimes follow their urges on the first warm day in the spring, or a sudden warm spell in the fall, to be outside with their pet. Often pets have not acclimated to the change in weather or the change in activity level and can develop heat stroke in such conditions. Always be cautious and limit exposure and gradually allow pets to build up more of a tolerance to heat and exercise under such conditions. 


What should owners do if they suspect their pet has heat stroke? 

While heat stroke is an urgent medical emergency and the pet should be taken to a veterinarian for immediate attention, there are some basic things pet owners can do to provide safe and controlled reduction of body temperature: get the pet into a cool, air-conditioned space as soon as possible; offer a cold drink of water; use wet towels or blankets to soak your pet’s fur quickly and allow them to be in front of a fan blowing cool air; transport the pet to the nearest veterinary facility. If the patient is severely affected, the veterinary team can arrange a referral to an emergency hospital such as OVC when safe to do so. 

What can pet owners do to feel prepared to deal with medical emergencies involving their pet (heat stroke or otherwise)? 

Educate themselves on common risks and avoid them. Always be aware where the closest veterinary care is, or utilize telemedicine services to assist in triage and initial assessment and advice. Have some basic first aid elements at home or travel with them. Peroxide (fresh, not expired, unopened), clean towels / bandages, elastic bandage and a blanket large enough to help transport a pet if needed.

Watch Daisy's story, a dog who was treated for heat stroke in OVC's Intensive Care Unit (ICU). 

Read more in the spring / summer issue of Best Friends Magazine