The information in this article was reviewed and approved by registered veterinary nurse, Beth Walker

Heatstroke is the most serious form of hyperthermia, and is sometimes also called sunstroke. Rather than sweating through their skin like we do, dogs cool themselves down by panting and releasing heat through their paw pads and nose. Sometimes, this isn’t enough to bring their body temperature down sufficiently. If a dog’s body temperature is too high, they are at risk of heatstroke, which can cause seizures, organ damage and even death. In this blog, we’ll detail the signs of heatstroke in dogs so that you can act quickly if your dog is overheating, and explain how to cool them down. Heatstroke is more dangerous the longer it lasts, so the quicker you cool your dog and see a vet, the better their chance of a full recovery.

How Hot is Too Hot for Dogs in the UK?

Most dogs are comfortable at temperatures between 15-25°C, but this will vary depending on many factors such as breed, age, coat type, weight, and whether or not they are exercising.

A dog’s normal body temperature is around 38-39°C. Hot weather, lack of ventilation and over-exertion can cause their temperature to get higher than this. If a dog’s body temperature goes above 40°C, they are at risk of heatstroke.

What Are the Three Stages of Heat-related Illness in Dogs?

There are three types of hyperthermia, which is the term used to describe an elevation in body temperature. These are heat stress, heat exhaustion, and heatstroke.

Of these three stages of heat-related illness, heatstroke is the most severe. Dogs may start off suffering from heat stress, and as the condition worsens, it may progress to heat exhaustion, and then to heatstroke.

However all three heat-related illnesses require immediate attention and can be very dangerous.

Symptoms of Heatstroke in Dogs

Some of the initial signs of heatstroke in dogs include:

• Panting (this might progress to more distressed breathing)
• Low energy or tiredness
• Drooling
• Foaming at the mouth
• Bright red gums (or sometimes they can appear very pale)
• Vomiting or diarrhoea (possibly containing blood)

As heatstroke progresses, your dog may also show the following symptoms:

• Stumbling or dizziness
• Confusion
• Seizures
• Collapse and unconsciousness

Heatstroke progresses quickly, so it’s important to be able to spot the early signs of heatstroke and act swiftly.

What to Do if Your Dog Shows Signs of Heatstroke

If you spot any of the signs of heatstroke in your dog, the most important thing to do is cool them down as quickly as possible. The more quickly you can bring their body temperature down, the more likely they are to make a recovery.

Here’s our step-by-step guide to carrying out heatstroke first aid for your dog:

1. Move your dog to a cool, well-ventilated place. This might be in a cool room indoors, or in a patch of shade. An air-conditioned room or car is ideal.
2. Wet their coat with cool (not freezing) water. You could use a water spray, hose or simply a cup or bottle filled with tap water – whatever you can get hold of quickest. If water is limited, you can sponge their body instead. Don’t use ice-cold water as this can cause shock. Be very careful that the water doesn’t go over your dog’s face as this could cause them to inhale the water.
3. Create a breeze. Fanning your dog when they are already wet will have the greatest impact on their body temperature. If you are inside, open windows and doors, and turn on an electric fan if you have one.
4. You can also put your dog on top of a towel that has been soaked in cold water. Never cover your dog in a towel though, as this can cause their body temperature to increase further. Similarly, you mustn’t cuddle them as this will also make them hotter.
5. Offer your dog cold water to drink – but don’t force them to drink it.
6. Call your vet as soon as you can. Cooling your dog should be the priority, but it’s very important to get advice from your vet quickly.
7. If your vet advises you to take your dog into your nearest practice, make sure the car is cool with the air-conditioning on or windows open. Sit your dog on a cold wet towel for the journey. Ideally have someone come with you who can continue to cool your dog with water.

How Long Does it Take a Dog to Fully Recover from Heatstroke?

This will vary a lot depending on the individual dog, and how severe the case of heatstroke is. In mild cases, if the dog is quickly cooled and taken to the vet urgently, a full recovery can be fairly quick.

However, sadly 1 in 7 dogs that are treated for heatstroke will still pass away. This is a more likely outcome for more serious cases of heatstroke, or scenarios where treatment is delayed.

These more severe cases will require more intensive treatment which will last longer, and dogs will take longer to fully recover.

This is why it’s very important to contact your vet right away if you think your dog has overheated.

What Causes Heatstroke in Dogs?

Most cases of heatstroke in dogs occur during exercise and playtime – three quarters of cases in fact. This is often during bouts of hot weather, but it doesn’t have to be ‘hot’ for dogs to develop heatstroke. Exercising can raise the body temperature significantly even in cooler weather. Never assume that your dog will know when to calm down and rest – exercise increases arousal for dogs, and they won’t necessarily slow down if they are overheating.

Heatstroke can also be caused by being trapped in a hot, unventilated space. A prime example of this is a car, which can reach scorching temperatures in just a few minutes. Contrary to popular belief, it’s not just during the summer that this happens. If the outside temperature is just 16°C, the temperature inside the car can climb as high as 38°C. You should never leave a dog in a car, for any length of time, even with the windows open.

Conservatories, garages, summer houses, and greenhouses are just a few examples of other spaces that can reach unbearable temperatures very quickly.

In some cases, dogs might develop heatstroke simply from sitting somewhere warm and sunny for too long. Always keep an eye out for the signs of heatstroke.

Which Dogs are Most Prone to Heatstroke?

All dogs can suffer from heatstroke, and it can happen at any time of year. However, some dogs are more at risk of heatstroke than others.

Specific breeds: Flat-faced (brachycephalic) breeds like pugs, bulldogs, and French bulldogs are more likely to overheat. This is because their very short muzzles make it more difficult for them to breath, and dogs usually dissipate heat through their nose to cool themselves down. Long-haired or thick-coated dogs are also more likely to suffer from heatstroke, as are giant breeds, because larger bodies tend to lose heat more slowly.

Elderly dogs and puppies: Very young and very old dogs often struggle to regulate their body temperature as effectively.

Overweight dogs: Fat is an insulator, so dogs carrying extra fat on their bodies will struggle to cool themselves down as effectively. Overweight dogs may also have additional strain on their body.

Dogs with medical conditions: Health problems, particularly those that affect the heart or respiratory system, can put a dog at higher risk of heatstroke.

Energetic dogs: Particularly when the weather turns hotter, dogs that like to exercise a lot run the risk of becoming exhausted and dehydrated in the heat, which can lead to heatstroke. Most cases of heatstroke occur in dogs during exercise.

Wrapping Up

It’s crucial to bring an overheated dog’s body temperature down as quickly as possible – the longer their temperature remains high, the more damage can be done. Contacting a vet for treatment as quickly as you can is also essential to helping your dog make a full recovery from heatstroke.

There are lots of things you can do to prevent heatstroke in dogs, including avoiding walks at the hottest times of day, ensuring your dog always has access to drinking water, providing cooling toys and frozen treats, and never leaving them in a car, even just for a few minutes. For more advice on keeping your dog cool in the summer heat, read our blog.

Heatstroke can affect cats too; read our blog for more information on the symptoms and treatment for our feline friends.