The Dangers of Heatstroke in Dogs

By: Lauren Strazdis, DVM

[printer-friendly version]

Dogs cannot regulate their body temperature by sweating like humans do because they only have a few sweat glands on their paw pads. They instead rely on evaporation by panting to cool off in hot environments. No matter how much a dog pants, there are some situations where they cannot prevent their body temperature from rising to dangerous levels. When the humidity outside is greater than 80%, which is a common occurrence in Texas, panting is no longer useful.

Overheating can lead to a life-threatening condition known as heatstroke. Heatstroke occurs in dogs when their core body temperature rises above 105.8°F. At this temperature, permanent neurological damage is possible. If the temperature continues to rise, multiple organ failure and death will likely occur without immediate treatment.

The most common cause of heatstroke is exposure to a hot environment, especially being left in a car in warm weather. Temperatures inside a car can increase compared to the outside temperature by nearly 20ºF in 10 minutes, 30ºF in 20 minutes, and over 40ºF in 60 minutes. This means if a dog is left in a car on a 75ºF day, the temperature inside the car will increase to 95ºF after 10 minutes and 105ºF after 20 minutes. After one hour, the car temperature would be 115ºF. Each of these temperatures could easily put the dog at risk for heatstroke and death. Leaving car windows partially open does not make a significant difference in keeping the dog cooler.

Other reasons for heatstroke include long exposure to a hot hair dryer and being left outside in warm weather without shade or water. Dogs that become very excited when playing outside or undergo strenuous exercise in warm weather are also at significant risk. Other risk factors for heatstroke include heart disease, neurologic disease, old age, or having a dark-colored or thick haircoat.

Bulldogs, Pugs, Shih Tzus, Boston Terriers, Cavalier King Charles Spaniels, Lhasa Apsos, Boxers and other flat-faced dogs are called brachycephalic breeds. They have abnormally formed airways that make them especially prone to heatstroke even when the outside temperature may not seem very high. They can easily become distressed and overheat as they struggle to breathe while trying to cool off.

Signs of heatstroke include excessive panting, drooling, vomiting, diarrhea, red or purple spots on the skin or gums, disorientation, seizures and collapse. If you notice any of these signs, it is critical that you immediately put the dog directly under air-conditioning or a high-powered fan, pour cool (not cold) water on their body and cover them with wet towels, then transport them immediately to the nearest veterinarian. The body temperature needs to be gradually lowered, so do not place ice or freezing cold water on the dog before going to the veterinarian.

If you see a dog locked in a car without air conditioning on a hot day and you are concerned for its safety, try to locate the owner as soon as possible. If the owner cannot be found, call the local police or animal control and wait by the car for further instructions or until they arrive.

For more information, visit the following link: