Heatstroke can be fatal in pets. It can affect any dog, but there are some breeds that are more susceptible to the detrimental effects of overheating. It’s important to be able to recognise the signs of heatstroke and know how to help prevent it. 

What is heatstroke?

You’ll probably be somewhat familiar with heatstroke because of our awareness of it in humans, the typical scenario of spending too long out in the sun on holiday! To give you a better insight into what happens in dogs, let’s look at the science behind it. 

Heatstroke occurs where there is an abnormal increase in body temperature that isn’t brought about by processes within the body itself. So, in short, caused by the external environmental temperature. For us veterinarians, it is used to describe a very serious course of events that follow the activation of inflammatory pathways within the body. Where the body temperature that isn’t compatible with normal cell functions. This can lead, in the worst cases, to organ failure and death of the pet.

Why does heatstroke occur?

Normal body temperature for dogs ranges between 38.1-39.0 degrees Celsius, although there is some variation. When the outside temperature increases, dogs pant to improve heat loss by evaporation. They also use conduction by lying in cool areas to promote heat loss and maintain a normal body temperature.

If the dog’s temperature rises and keeps on rising because the temperature is too high outside, they can’t find shade, or they are overexerting themselves, then these mechanisms become much less effective. The dog’s temperature gets too high, cell functions are affected and detrimental complications can begin. 

It should be noted that not all dogs will suffer heatstroke under the same conditions. Obviously, any dog left in a hot car will be at high risk of heatstroke. However, what often isn’t appreciated is that snub-nosed (brachycephalic) breeds are at much higher risk of the illness; even when the temperature outside isn’t that high.

This is because these dogs are anatomically inefficient at heat loss. They also live with some degree of respiratory compromise. Together, these issues make it very difficult for them to maintain normal heat loss mechanisms and respiratory function, even at only mildly elevated temperatures. This is why we would always advise that such dogs are not walked, or walked in the cooler hours, even when it’s only a little warmer outside. 

What are the signs of heatstroke?

Heatstroke causes an inflammatory response in the body and can cause cell death. Signs of this might include;

  • collapse
  • unconsciousness
  • seizures
  • difficulty breathing
  • bleeding problems
  • bloody diarrhoea
  • clotting problems

Many dogs are in shock, which means they often have a very fast heart rate with pulses that are difficult to feel. It also means that whilst their body temperature might have been too high to start with, the effects of being in shock might mean their temperature is normal or even too low.

The signs tend to get progressively worse if untreated. So whilst the dog might start off just heavily panting or being unwilling to get up, it can quickly progress to having more serious signs.

If you suspect your dog has heatstroke – get them to the vet ASAP.

How to help prevent heatstroke 

The most important takeaway message is trying to prevent heatstroke from happening in the first place. We all love warmer weather, but, in reality, our pets aren’t accustomed to it. Whilst it might seem a lovely idea to have a long walk in the sun, or a good bout of playtime in the garden on a warm day, it’s really best to leave your dog in a cool, shady place at home with plenty of water. Opt for a walk and more activity when it’s cooler.

As mentioned above, whilst this applies to all dogs, it’s so important for brachycephalic breeds who really are very susceptible to this fatal illness. Try to be heat safe with your dog to prevent them from succumbing to heatstroke. 

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