How heatstroke happens, which dogs are most at risk, the warning signs, emergency cooling first aid, and practical ways to keep dogs safe on walks, at home and in cars.
This guide is general information, not a substitute for advice from your vet. If you are worried about your dog, contact your vet or an out-of-hours vet service.
Dogs cool down mainly by panting, which is far less efficient than sweating. In hot or humid weather they can overheat quickly, and heatstroke can be fatal. Vets and animal charities in the UK warn every summer that most cases are preventable. Here is what to watch for and what to do.
Which dogs are most at risk?
- Flat-faced (brachycephalic) breeds such as French bulldogs, pugs and bulldogs, whose airways make panting less effective.
- Overweight dogs.
- Older dogs and young puppies.
- Dogs with heart or breathing conditions.
- Thick-coated breeds and dogs with dark coats in direct sun.
- Very active dogs, who will keep playing even when overheating.
Warning signs of heatstroke
- heavy, noisy panting and difficulty breathing;
- excessive drooling;
- bright red or dark gums and tongue;
- lethargy, confusion, stumbling or collapse;
- vomiting or diarrhoea;
- seizures.
Heatstroke is an emergency. If you see these signs, start cooling your dog and contact a vet at once.
Emergency first aid: step by step
- Move your dog to a cool, shaded place straight away.
- Call your vet and tell them you are on your way.
- Start cooling: pour cool (not ice-cold) water over your dog's body, or use wet towels and replace them often so they don't trap heat. Recent veterinary advice is that cooling quickly with any cool water available is what matters most: "cool first, then transport".
- Use moving air: a fan or the car's air conditioning helps.
- Offer small amounts of water to drink if your dog is alert, but don't force it.
- Get to the vet even if your dog seems to recover, as heatstroke can cause internal damage that isn't obvious at first.
Walks
- Walk early in the morning or late in the evening, when it is cooler.
- Check the pavement: place the back of your hand on it for about seven seconds. If it is too hot for you, it is too hot for paws.
- Shorten walks and keep to shade. Skipping a walk on a very hot day is fine; offer games and enrichment at home instead.
- Avoid strenuous exercise such as ball throwing in the heat.
- Carry water and a bowl.
Cars: never leave a dog alone
Cars heat up very quickly, even on days that don't feel especially hot, and leaving windows open or parking in shade makes little difference. Never leave a dog in a parked car. If you see a dog in distress in a hot car, call 999: the police can help. The RSPCA advises on what to do if you think a dog is in danger.
On journeys, keep the car cool, take water, and plan breaks.
At home
- Make sure your dog always has shade and plenty of fresh water.
- Keep curtains closed in sunny rooms.
- Provide cool surfaces, such as a damp towel or a cooling mat.
- Frozen treats, such as a stuffed food toy frozen overnight, give enrichment and cooling.
- A paddling pool in the shade suits many dogs.
- Don't leave dogs in conservatories, caravans or outbuildings, which can get very hot.
Sun, water and other summer risks
- Dogs with pale or thin coats, or pink noses and ears, can get sunburnt. Ask your vet about pet-safe sun cream.
- Blue-green algae in ponds and lakes can be deadly. Keep dogs out of water that looks discoloured or scummy, and look for warning signs.
- Watch for grass seeds in ears and paws after walks.
Frequently asked questions
Should I shave my dog's coat?
Not without advice. Some coats help insulate against heat. Regular grooming to remove dead undercoat is often better; ask a vet or groomer.
Sources and further reading
Facts checked on 20 October 2026. Spotted an error? Tell us and we will correct it.