We all know that dogs don't sweat--except for a teeny bit through their feet. They depend on panting to exchange hot air for cool, but when the outside air is the same as their inside air, that form of air conditioning isn't so efficient.
Being left in a car during hot weather, confined on concrete or asphalt surfaces, and being without shade or fresh water on hot days can lead to heat stroke. Did you know that Pugs, Pekinese and Bulldogs are more prone to heat stroke because of their cute little noses?
What does heat stroke in dogs look like? It starts with heavy breathing, the tongue looks bright red, saliva thickens and the dog may vomit. (The body temperature also rises to over 104 degrees, but most of us don't have a rectal thermometer handy to check that.) If shock sets in, the lips turn gray and the dog may become unsteady and collapse.
So what do you do now? First, you must cool the dog at once. Usually moving him to an air-conditioned area is sufficient, but sometimes it is necessary to place the dog in a cool bath or spray him gently with a garden hose for a few minutes. Be careful not to cool too much or too rapidly, because that causes another problem: hypothermia and shock.
Always, always follow up with your veterinarian if you believe your dog has suffered heat stroke to avoid other complications.