Heat stroke is simply when dogs become too hot and can not regulate it any longer. It is often referred to medically as hyperthermia, without previous signs of illness but associated with external or environmental heat.
As humans, we regulate our body temperature by sweating among other mechanisms; we sweat profusely when we are hot but dogs on the other hands do not sweat like humans.
Panting is the primary way they getting rid of excess heat in the body. Even though they have sweat glands beneath their paws, this is not always enough to regulate heat.
Heat stroke can be very lethal and some dogs are prone to heatstroke than others, for example; very mature dogs or puppies, dogs with thick coat or brachycephalic dogs (smushed faces) like pugs and bull dogs.
Heat stroke in dogs can cause multiple organ failure or sudden death.
Major signs include: heavy panting, drooling, red or purple tongue or gums, rapid heart rate and pulse, dizziness, and sometimes, vomitting. Also, the dog may stagger or collapse from the heat exhaustion.
Most causes of heat stroke in dogs is as a result of carelessness and negliegience of the owners, such as like leaving a dog in a car without adequate ventilation, transporting a dog in a car in the heat of the day without air conditioner or any other ventilating means , leaving or tying a dog down in the sun, muzzling a dog for too long, leaving a dog in a cage without water on a hot day, and walking a dog on really long distances.
The first aid for a hyperthemic dog is to take such to a properly ventilated area. Also, make efforts to reduce its body temperature by wetting thoroughly with cool water. DO NOT use cold water as cooling off the temperature too quickly can cause undesired effects.
Use a damp towel for tepid bath, focusing on the armpits, chest, belly and inner thighs, put them in front of a fan or air conditioner, provide water for them to drink, call your vet or take to the vet as soon as possible.