What is heatstroke?
Updated By PetymFacts checked against official sources on
Quick answer
Heatstroke is a dangerous rise in body temperature that can damage organs and kill. In dogs it most often follows exercise in heat, not hot cars. Heavy panting, drooling, vomiting, wobbliness and collapse are the signs. Start cooling the pet on the spot with plenty of cool running water and moving air, then go straight to a vet.
Also called heat stroke, heat-related illness, hyperthermia, sunstroke in dogs.
Key facts
- Exercise triggered 74.2% of heat-related illness cases in UK dogs; hot surroundings 12.9% and vehicles 5.2%. Animals (2020)study
- Flat-faced breeds had about twice the odds of heat-related illness of medium-nosed dogs in a large UK study. Scientific Reports (2020)study
- Dogs aged 12 or older, and dogs at or above their breed's average weight, had higher odds. Scientific Reports (2020)study
- The 2026 RECOVER first-aid guidelines advise cooling on the spot, before travelling, with cool running water over the body. RECOVER Initiative (Journal of Veterinary Emergency and Critical Care, 2026)study
- A parked car in the sun can heat by about 20 to 25 °C above the outside air within an hour. RSPCA (England and Wales)
What are the signs of heatstroke in a dog or cat?
Act on early signs. Heatstroke can move from heavy panting to collapse quickly.
- Heavy, rapid panting that does not settle with rest in the shade. RSPCA (England and Wales)
- Drooling, and hot skin to the touch. RSPCA (England and Wales)
- Vomiting or diarrhoea. RSPCA (England and Wales)
- Lethargy and a rapid heartbeat, which the Animal Welfare Board of India lists for hot weather. Animal Welfare Board of India
- Wobbly walking, confusion or distress. RSPCA (England and Wales)
- Collapse or unconsciousness: an emergency. Merck Veterinary Manual
What should you do straight away?
Move the pet out of the heat into shade or a cool room. Start cooling at once: pour plenty of cool running water over the body and belly, away from the face, and use a fan or moving air. The 2026 RECOVER first-aid guidelines say to cool on the spot before you travel, and not to put a pet in a tub or sink because of the risk of drowning. Do not cover a hot dog with wet towels, which trap heat.
Then go straight to a vet in a cool car, phoning ahead. Go even if the pet seems to recover, because heatstroke can damage organs in ways that show later. Offer small sips of water only once it is alert and cooling.
Which pets are most at risk in an Indian summer?
Flat-faced breeds such as the Pug, Bulldog, French Bulldog and Shih Tzu, older dogs, heavy dogs and thick-coated breeds such as the Siberian Husky need the most care. Short-nosed dogs can overheat from excitement or stress even on a cool day. Cats can get heatstroke too, especially if shut in a hot room, a car or a carrier.
In India the risky hours run long: from late morning to early evening in April, May and June across the north and centre and in the humid heat of the coasts and the monsoon build-up. Walk in the early morning and late evening, keep paws off hot roads at midday, and plan for power cuts, when a closed flat with no fan heats up fast.
How dangerous is heatstroke?
About 1 in 7 dogs with heat-related illness died in UK vet-practice records, and in an Israeli hospital study about half of dogs with severe heatstroke died even with treatment. Cooling on the spot, before the drive to the vet, is the step first-aid guidelines put first. Under the Prevention of Cruelty to Animals Act, 1960, anyone in charge of an animal must take reasonable care of it, a duty the Animal Welfare Board of India cites for hot weather.
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Questions owners ask
What temperature is too hot to walk a dog in India?
- No single number fits every dog. Heat, humidity, breed, age, weight and how hard the dog exercises all matter, and most heatstroke cases in a large UK study followed exercise. In an Indian summer, walk flat-faced, old, heavy and thick-coated dogs only in the early morning and late evening, and keep walks short.
Should I put ice on a dog with heatstroke?
- Use plenty of cool running water and moving air instead. The 2026 RECOVER first-aid guidelines recommend cool water poured over the body on the spot, before travelling to a vet. Never cover a hot dog with wet towels, which trap heat, and never put an unconscious dog in water.
Can cats get heatstroke?
- Yes. A cat shut in a hot room, a car, a carrier in the sun, or a flat without fans during a power cut can overheat. Signs include panting, drooling, restlessness and collapse. Cool the cat with water and moving air and go straight to a vet.
Does a dog need a vet after heatstroke if it seems fine?
- Yes. Heatstroke can damage the kidneys, gut and blood clotting in ways that show hours later, and a dog can seem to recover and then worsen. Cool the dog first, then take it to a vet even if it is alert and drinking again.
Keep reading
Related terms
More in health conditions
- ArthritisArthritis, or osteoarthritis, is a long-term joint disease in which worn cartilage lets the joint surfaces rub, causing stiffness, swelling and pain. It is very common in older dogs and cats. It cannot be cured, but pain relief from a vet, a healthy weight, gentle regular exercise and a few home changes keep most pets comfortable for years.
- Bloat (GDV)Bloat, or gastric dilatation-volvulus (GDV), is when a dog's stomach fills with gas and twists on itself, cutting off its blood supply. It mainly affects large and giant deep-chested breeds. Unproductive retching, a swelling belly, drooling and restlessness are the signs. It is a surgical emergency that can kill within hours.
- BOASBOAS, brachycephalic obstructive airway syndrome, is a breathing disorder of flat-faced dogs. Narrow nostrils, an overlong soft palate and a small windpipe block airflow, so affected dogs snore, snort, tire quickly and overheat easily. It is worse in heat, humidity and obesity. Surgery can widen the airway, and a lean weight helps.
- Canine distemperCanine distemper is a serious viral disease of dogs that can attack the skin, airways, gut and nervous system. It spreads in droplets from coughing, sneezing and barking, and through body fluids. There is no specific cure, and some dogs do not survive even with treatment. The D in the DHPPi vaccine prevents it.
- Canine parvovirusCanine parvovirus, or parvo, is a highly contagious virus that attacks a dog's gut and immune system. It spreads through infected faeces, survives a long time in the environment and hits unvaccinated puppies between 6 weeks and 6 months hardest. Vomiting and bloody diarrhoea can kill within days, and it is prevented by the core vaccine.
- Cat fluCat flu is the everyday name for an upper respiratory infection in cats. More than 90% of cases are caused by feline herpesvirus, feline calicivirus or both. Cats sneeze, have runny eyes and nose and may stop eating. Most recovered cats remain carriers, and stress can bring the virus back. Vaccination usually prevents severe disease.
- Cherry eyeCherry eye is when the tear gland inside a dog's third eyelid slips out of place and shows as a smooth, red, cherry-like lump in the inner corner of the eye. It is common in young Bulldogs, Beagles, Shih Tzus and Pugs, and needs a vet, usually for surgery to put the gland back.
- Chronic kidney diseaseChronic kidney disease (CKD) is a slow, lasting loss of kidney function, common in older cats and also seen in older dogs. Early on there are often no signs; later a pet drinks and urinates more, eats less and loses weight. It cannot be cured, but a kidney diet, water and regular checks can slow it.
- DehydrationDehydration means a pet's body has lost more water than it has taken in, through heat, panting, vomiting, diarrhoea or illness. Early on the gums turn sticky; then the skin loses its spring and the eyes sink. A mildly dehydrated pet needs water and a watchful eye; a weak, vomiting or collapsing one needs a vet now.
- Dental diseaseDental disease in pets is mostly periodontal disease: plaque bacteria inflame the gums (gingivitis) and then destroy the tissue and bone holding the teeth (periodontitis). It is the most common disorder vets diagnose in dogs, and very common in cats. Bad breath, tartar and red gums are the early signs. Daily brushing prevents most of it.
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Sources
Each source was opened and read on the date shown. How Petym checks its sources
- RSPCA (England and Wales): Dogs die in hot cars (opens in a new tab)
- RSPCA (England and Wales): How to recognise and treat heatstroke in dogs (opens in a new tab)
- Animal Welfare Board of India: Request to ensure care and protection of animals from direct heat during extreme hot weather (4 May 2026) (opens in a new tab)
- Merck Veterinary Manual: What to do in a dog or cat emergency (opens in a new tab)
- PDSA: Heatstroke in dogs (opens in a new tab)
- Merck Veterinary Manual: Description of dogs (opens in a new tab)
Show all 14 sourcesShow fewer
- Animals (2020): Dogs don't die just in hot cars: exertional heat-related illness (opens in a new tab)
- Scientific Reports (2020): Incidence and risk factors for heat-related illness in UK dogs (opens in a new tab)
- RECOVER Initiative (Journal of Veterinary Emergency and Critical Care, 2026): RECOVER guidelines: first aid for dogs and cats, clinical guidelines (opens in a new tab)
- RECOVER Initiative (Journal of Veterinary Emergency and Critical Care, 2026): RECOVER guidelines: first aid in dogs and cats, evidence and knowledge-gap analysis (opens in a new tab)
- Temperature (2017), Hebrew University: Pathophysiology of heatstroke in dogs, revisited (opens in a new tab)
- Journal of Veterinary Internal Medicine (2006), Hebrew University: Heat stroke in dogs: a retrospective study of 54 cases and risk factors for death (opens in a new tab)
- Veterinary Sciences (2023), Royal Veterinary College: Cooling methods used to manage heat-related illness in dogs (opens in a new tab)
- Veterinary Evidence (2022), RCVS Knowledge: Heatstroke and brachycephalic dogs: is there an increased risk? (Knowledge Summary) (opens in a new tab)