Overview
Heat stroke in dogs is a serious and potentially life-threatening condition. It happens when a dog gets too hot and can't cool down. Unlike humans, who can sweat freely all over their bodies, dogs can only sweat through their noses and the bottoms of their paws. They mainly cool down by panting, breathing out warm air and drawing in cooler air through their mouths and tongues. If this system is overwhelmed, their body temperature can rise dangerously fast.
As temperatures rise, it’s important to know how to spot the signs of heat stroke early and act quickly. Some dogs are more at risk than others, but any dog can overheat, even on a mild day. There are ways to keep a dog cool, but as a dog's body temperature continues to rise, their organs begin to shut down. Severe heat stroke can be fatal for dogs, and cases are becoming more common.
What causes heat stroke in dogs?
The most common triggers of heat stroke in dogs include:
Exercising in warm weather.
Being stuck in a hot car.
Getting trapped in a greenhouse, conservatory, or outbuilding.
Poorly ventilated or shaded areas.
Some dogs are more at risk, including flat-faced breeds like pugs or bulldogs, puppies and older dogs, overweight dogs, dogs with thick coats, and dogs with heart or breathing problems. Even a short walk on a hot or humid day can cause your dog to overheat, especially if they're in these high-risk categories.
Signs of heat stroke in dogs
Your dog may be suffering from heat stroke if they display any of these signs:
Fast, heavy breathing or panting
A bright red tongue
Sticky gums
Excessive drooling
Vomiting
Confusion
Circling
General restlessness
Dizziness (your dog may appear lethargic, drowsy, or slow)
These heat stroke symptoms can also indicate other conditions, but during warm weather, heat stroke is a strong possibility.
How to treat heat stroke in dogs
Firstly, don’t panic. Act quickly but stay calm. Visibly worried behaviour will affect your dog and cause their body temperature to rise further.
Seek shade: your first action should be to remove your dog from any direct sunlight.
Cool first, transport second: studies show the most effective way to treat heat stroke is rapid cooling. Cold water immersion is most effective for healthy dogs. For older dogs with health conditions, or those who may struggle with immersion, pour cool water over their body and combine it with airflow from a fan, breeze, or air conditioning (known as evaporative cooling).
Focus on the belly, armpits, and paws: if full immersion isn't an option, cooling these areas first can help lower their core temperature more quickly.
Offer small amounts of drinking water: gradually let your dog drink cool water in small amounts.
Can you treat heat stroke at home?
You can start first aid by acting quickly and following the instructions above, but your dog will still need professional care. Even if your dog seems to improve, contact your vet and bring them in for a check (but take steps to keep your dog safe while bringing them to the vet in the hot weather). Some symptoms and complications can appear later. Rapid cooling and veterinary care give your dog the best chance of recovery.
What not to do if your dog has heat stroke
When you're trying to help your dog, steer clear of these common mistakes:
Don’t cover your dog with wet towels because this can trap heat and block evaporation. If using a towel, place it underneath them, not over their body.
Don’t delay veterinary care even if your dog seems better, as internal complications can still develop.
Don’t force them to drink. Encourage small sips, but forcing water may cause choking or inhalation.
Don’t assume mild weather is risk-free. Heat stroke can happen on overcast days or in high humidity, especially with poor airflow.
How to prevent heat stroke in dogs
With preparation and by knowing how to keep your dog cool, you can drastically reduce the chance of your dog getting heat stroke:
Ensure your dog has access to shade at all times.
Bring water out on walks, for your dog as well as for you.
Avoid walking your dog at hotter parts of the day.
When out walking your dog, take regular stops in shaded areas.
Use sun cream on dogs with pale or thin fur.
Don’t walk your dog on a pavement (or artificial lawn) that’s too hot.
Never leave your dog alone in the car.
Read more: Things dog owners should never do during summer
Vet's view
By Lizzie Youens BSc(Hons) BVSc MRCVS
I was spending a sunny July weekend on-call at the veterinary hospital, and had been hearing the noise of the town summer fete all morning. That afternoon, an elderly pug was rushed in, and I could hear his laboured breathing before I even got into the consulting room. The whole family had been at the fete, and although they’d tried to keep their dog cool by leaving out a water bowl and tried to keep him in the shade, he became very lethargic and then suddenly collapsed.
I assessed the dog immediately. Large amounts of thick saliva were coming from the dog's mouth, and his breathing was very laboured and fast. The dog's high heart rate, abnormal gum colour and extremely high rectal temperature confirmed a diagnosis of heat stroke. He was extremely weak and I was very concerned about him. Flat-faced (brachycephalic) dogs are more susceptible to heat-related illness, including heat stroke, and their elderly bodies were under severe strain.
A busy and worrying few hours followed, with him under continual assessment. Initially, he started to seizure and I thought we might be too late to save him. However, with some intense active cooling with fans, ice packs, cold water and intravenous fluids, as well as some medication to control the seizures and stop the muscle tremors, the dog's vital signs gradually returned to normal. It was a very close call for what should have been a fun day out at the fete.
Read more: Taking your dog on holiday
How quickly can heat stroke happen?
In dangerous conditions, it can happen in under 30 minutes. That's why it’s crucial to spot the signs early and act fast.
Need more info?
Heat stroke is serious but preventable. By understanding the risks, watching out for signs and knowing what to do, you can keep your dog safe in the summer. If your dog ever needs us, we’re here to help. Unlimited vet consults are included in your Pet Health Club plan, so you can always ask for advice when you need it. Find your nearest vet using our find a vet page.
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Medically reviewed by Edward Davies, BVSc MRCVS, Sarah Colegrave, MA VetMB BSAVA PGCertSAECC MRCVS
Published on 29/04/2019 • Reviewed on 14/07/2025