Compared to humans, dogs are quite susceptible to overheating because they don't have any sweat glands, except on the pads of their feet. Dogs rely on panting to dispel heat. This works by speeding up the evaporation of water from the surface of the tongue. Dogs with short muzzles and heavy coated breeds in warm climates are at increased risk of heat stress. Dogs suffering from an underlying disease such as lung or heart disease are also less able to cope with high temperatures.
Unfortunately, heat stress most often occurs when dogs are left in cars. Cars act like glasshouses when left in the sun, heating up very quickly, even in mild weather. The temperature in a parked car can easily rise above 50°C in a very short time. The resulting high temperatures together with the high humidity in an enclosed car rapidly overwhelm the dog's cooling mechanism. The obvious solution is to never leave your dog in a parked car. Even with the windows open your dog can quickly suffer heat stroke and die.
Avoiding heat stress is mainly a matter of common sense. All dogs need appropriate shelter out of doors and access to plenty of cool drinking water. Dogs should not be exercised excessively in hot humid weather.
Heat stroke or Hyperthermia in dogs is an emergency situation requiring immediate attention. A dog can endure body temperature increases for only a short time.
Signs of heatstroke are excessive panting or difficulty breathing, a body temperature above 44 degrees (normal temperature is 38- 39 degrees), collapse, bloody diarrhoea or vomit, depression, stupor, seizures or coma.
First aid required:
Get your dog out of direct heat
Hose the dog with cool (not cold) water
Place water soaked towels on the head, neck, feet, chest and abdomen
Point a fan in the dog's direction
Take him to the nearest veterinarian immediately. Some problems may not show up for hours or days.