|Dangers: Overweight or obese dogs, large breed dogs, those with heavy muscling (pit bulls, boxers), or those that are brachycephalic (i.e., smooshed-nosed dogs like English bulldogs, French bulldogs, Shih Tzus, and pugs) are predisposed to overheating due their poor ability to dissipate heat. Dogs with health problems like laryngeal paralysis (an airway cartilage abnormality that results in loud, noisy breathing or a change in bark) are also predisposed to heat stroke. Any dogs carrying tennis balls in their mouths are also at risk because their airway is blocked, preventing adequate panting and cooling.
The most dangerous temperature is often 80 degrees Fahrenheit in the presence of 70 percent or 80 percent humidity. At this temperature—and higher temperatures—less evaporative cooling and heat loss take place so the body is unable to cool itself well through panting.
Cats and dogs inside closed cars—even with the windows slightly open—that are exposed to direct sun face a dangerous risk of heat stroke. Even when the temperature is as low as 75 degrees Fahrenheit, the inside of a car can heat up to 120 degrees Fahrenheit in less than 20 minutes, resulting in death in less than an hour.
Clinical signs: Signs of heat stroke while exercising: constant panting, slowing down, collapse, dark red gums, little urine production (or very concentrated, yellow/brown urine), and lethargy. Pets with heat stroke frequently have body temperatures greater than 108 degrees Fahrenheit, which often leads to permanent organ damage (kidney failure, bloody diarrhea), altered clotting (disseminated intravascular coagulation), or death.
Treatment: If any of these signs occur, it is imperative for pet owners to cool their pets immediately in a pond or pool and immediately call their veterinarian. Treatment includes rapid whole-body cooling with cool water baths (not ice), fans, cold towels, and alcohol applied to the paw pads. Aggressive therapy with IV fluids, IV protein (colloids), electrolyte and blood glucose monitoring, plasma transfusions, urine output monitoring, and supportive care are necessary for survival.
Prognosis: Good if treated early and before the body temperature has reached critical levels. Prevention is key—pet owners should carry a water bottle and offer fresh, cool water frequently to their dog, and to keep their pet wet and cooled during walks in hot weather if possible.
Next July Fourth danger: Picnic foods