During summer heat stroke is a common problem for dogs. Dogs have an extremely limited ability to sweat and their only real way to cool off if by panting, which unfortunately is not very efficient. Dogs were not bred as hot weather daytime athletes, and in the wild generally do most of their activity at dawn and dusk. The normal body temperature in a dog is between 37.5-39.5°C. As a dog exercises their body temperature can rise rapidly, and danger levels can develop with 30 minutes of vigorous exercise. At 40°C a dog will vigorously pant. At 41°C a dog will develop heatstroke. At 42°C a dog is in a life-threatening emergency.
Signs of heatstroke include extremely heavy panting, being dazed, confused, staggering and passing blood in the urine. If you suspect your dog has heatstroke you should stop walking immediately, pour cool water all over the dog, allow them to cool then carry them to a car or taxi and seek veterinary attention immediately. As well as the immediate damage, heatstroke can cause permanent organ problems if it is not treated.
To prevent heatstroke, be careful walking dogs during the hot weather. In the middle of summer dogs should only go out in the cool mornings and evenings, and if a lunchtime walk is necessary just make it very short. If you are sweating on a walk, pour water over your dog to allow them to cool, and stop every 15 minutes to allow your dog to drink. Remember that many dogs are very enthusiastic out on a walk and will over-exert themselves before they realise how hot they are.