Just don’t do it ..the risk is just not worth it and people in Arizona are very proactive when they see a pet on a car in the summer.
Other than the car heat stroke happens in any circumstance where the dog cannot get rid of the heat. Panting is a very inefficient heat loss mechanism. And certain breeds especially those that are have the short muzzles such as pugs and bulldogs and shih Tzu or Lhasa Apso. These breeds are called brachycephalic and because of their short muzzles and other changes in their airways they can become overheated in modestly high temperatures. Occasionally a pet may get affected in direct sunlight despite a reasonable air temperature.
Symptoms include crazy panting pacing restlessness ..the panting gets ever more severe and the pet may look weak and may collapse.
Heat stoke leads to a cascade of reactions in the body that if left untreated will lead to death. The major thrust is to lower the body temperature. These pets should be presented to a clinic as an emergency but if that was not possible for whatever reason then steps that can be taken include submerging the pet or wetting the pet in a cool but not cold shower or hose…fans can be used..ice cubes wrapped in cloth on the pads and ears ..the temperature in a dog with heat stroke can easily reach 106 -107…in a hospital situation we measure the temperature and stop cooling efforts when the temp reaches 103 or less. This prevents the opposite effect of making the patient too cold. The high temperature can lead to brain swelling heart and respiratory failure ..blood clotting problems ..shock ..these are serious cases and should be treated as emergencies