Heatstroke in dogs: a potential killer that's easy to avoid

"Every summer, dogs in Hong Kong die from preventable heatstroke, often with owners who really should know better. Pet owners, please take note: it does not take long for a walk in the sun to turn to disaster. I have seen dogs die from heatstroke after only out walking for less than an hour."

Heatstroke, the vet says, is a situation where the body temperature remains above normal for an extended period of time - and the higher the temperature, the faster the damage to vital organs and the less reversible the damage.

Kenda explains that there are two main ways to release heat from the body - conduction and evaporation. Conduction is obstructed when the dog has a thick coat. Heat loss from a dog's body is mostly by evaporation. "However, unlike us, dogs do not have sweat glands over their body, only in their paws, and these are not used for heat loss. The most effective way for a dog to lose heat is by panting."

The dog's tongue hangs out and is very pink as the blood vessels dilate to enable the blood to be cooled by the evaporative process, and the dog will breathe rapidly to exchange the air as fast as possible. "Remember that this evaporative cooling implies that moisture is lost from the dog's body. This moisture needs to be replaced by drinking. Otherwise, the dog will rapidly dehydrate."

Generally, evaporative cooling by panting is a good technique to release heat, the vet says. But in a Hong Kong summer this method is not as efficient. "Unfortunately, the effectiveness of evaporative heat loss diminishes when the humidity is 70 per cent or more, which is almost every day here during summer."