Dogs cool from the bottom-up. This means that the fastest way to cool a dog is by cooling its abdomen or genital area. This is why, during hot summer months, a dog can often be found laying in a hole that it has dug- the cool earth acts as a system to remove heat from the dog's underside.

Some dogs are predisposed to heat stroke, and suffer from it more easily and more frequently than others- especially large breed dogs, and dogs with short noses; like Mastiffs, Pugs, and Boxers. Heat stroke can be deadly in any dog, so prevention is extremely important. Some important steps to aid in prevention are:

Fresh water available at all times

The colder the water, the better. Some people may serve their dog frozen blocks of water in a large dish; this helps to keep the melting water as cold as possible. In addition, your dog's water must be changed regularly, as many dogs will not drink dirty water, even if they are suffering from heat stroke.

Slow or restricted exercise

On very hot days, you should restrict your dog's activity level. Dogs are not adept at doing this on their own, and will often overwork or over-play themselves to the point of heat exhaustion, and even heat stroke. Allow your dog slow exercise, and remove them to a cool area afterwards.

Cool areas

Your dog should have access to shade at all times, and should never be left exposed to the sun. Humidity plays an important role in this as well. Your dog can easily perish in such environments as a car, a greenhouse, an attic, or while on a concrete run. Air-conditioned and well-shaded areas are best. Also, never kennel your dog in a closed plastic crate or kennel. Only kennel in an open-wire kennel. Even in cool weather, a large dog can increase the temperature inside of a plastic kennel very rapidly simply by panting and emitting body heat. Be aware that your dog can suffer from heat stroke even while in the water. In fact, swimming requires a major expenditure of energy, and so heat stroke while in the water is not uncommon.

Cool your dog down at the first sign of heat stroke. Signs can be any or all of the following:

Excessive panting

Profuse salivation

Dry gums and mouth

Hyper-ventilating

Weakness or exhaustion

Confusion

Vomiting or diarrhea, sometimes with blood

If your dog is exhibiting these signs, or you recognize any other signs that you attribute to heat stroke, you need to begin treatment immediately. Start by removing your dog to a cool area. If possible, take their temperature, preferably using a rectal thermometer. Temperatures around 105-106 are serious. Temperatures at 107 or higher are to be considered a critical, life-threatening emergency. Once you have removed your dog to a cool area, continue treatment by immersing your pet in a cool tub of water, or by gently dousing them with a hose. If your dog's temperature is over 106, or exhibiting signs of confusion or weakness, then you should administer a cold water enema to cool your dog's internal temperature. If your dog requires emergency medical treatment, this may involve an injection of cortisone, and often a dog experiencing heat stroke will have a very swollen throat.

The most important thing for you to remember when treating your dog for heat stroke is avoid panic, be prepared, and stay cool!