Heatstroke occurs when a dog’s body either produces through exercise or absorbs from the environment more heat than it can dissipate. When the temperature reaches 109° degrees Fahrenheit or greater, heatstroke occurs and the cells of the body begin to die quickly. Swelling of the brain causes seizures, lack of blood supply to digestive tract causes gastric ulcers and dehydration leads to permanent damage to the kidneys, all within a matter of minutes.
You may be surprised to learn how easily heatstroke can occur. We usually think of heatstroke occurring when a dog exercises too much in hot weather or is left in a locked hot car, but there are reports of dogs suffering severe heatstroke while walking with their owner on a hot day or when exposed to direct sun through the window of a moving car. A dog maybe susceptible to heatstroke under conditions that might not be uncomfortable, much less life threatening for humans.
One reason dogs are more susceptible to the effects of heat than humans is their skin is different. Human skin has many sweat glands in it, and beneath the surface of the skin is a vast network of tiny blood vessels called capillaries. When the human body becomes overheated, the glands produce sweat and the blood in the capillaries is cooled as the sweat evaporates. Dogs have neither the sweat glands nor the blood cooling capillaries of humans. They cool themselves by panting, allowing cooler air to enter the lungs and dissipate their body heat. Older dogs, puppies, sick dogs and dogs poorly acclimated to warm weather are especially at risk, but even healthy dogs who live outdoors all the time may be susceptible during severe hot weather or excessive exercise or excitement.
Dogs with small heads and short noses, such as Pekingese, Boxers, Bostons, Bulldogs, or Chinese Pugs are more susceptible to heatstroke. They are poorly built for cooling by panting, so they can’t exchange air as easily as long nosed dogs.
Signs of heatstroke are: loud and excessive panting, profuse salivation, restlessness and dry gums and tongue. The gums and tongue turn bright red to purple, eyes become glazed and they have trouble walking or standing.
If you think your dog is suffering from heatstroke, take action. First, get the dog out of heat into shade or in air conditioning as soon as possible. Offer him small amounts of cold water. Call a veterinarian and get him examined as soon as possible.