Understanding Heatstroke in Cats: Symptoms, Prevention, and Treatment

Most people end up here after one of two moments: a cat found shut in a hot room, car, shed or sunroom, or a cat suddenly panting and drooling on a warm day. Heatstroke is the point where overheating stops being “a bit much” and starts damaging organs.

The safest approach is simple and fast: recognise the early signs, cool your cat gradually (not with ice), and get veterinary help even if they seem to rally. Heatstroke can look better on the outside while trouble continues inside.^{1, 2}

What heatstroke is (and why cats can tip over quickly)

Heatstroke (also called severe hyperthermia) happens when a cat’s body temperature rises high enough that normal cooling can’t keep up. Cats don’t sweat like people; they shed heat by seeking cooler places, grooming, stretching out on cool surfaces, and breathing a little faster. In still, humid heat—or when they’re trapped with no escape—those strategies can fail.³

Heatstroke is a medical emergency. It can become life-threatening quickly and can lead to complications that only show up hours later, which is why vets recommend an urgent check even after home cooling starts.^{2, 4}

Common causes of heatstroke in cats

Heatstroke usually begins with a cat stuck in heat they can’t move away from. The classic traps are quiet and ordinary: a sun-baked car, a closed room without airflow, or an outbuilding that turns into an oven by mid-morning.^{3, 5}

• Confinement in hot spaces: cars, garages, sheds, greenhouses, closed sunrooms, laundries and bathrooms with poor ventilation.^{3, 5}
• High ambient heat and humidity: especially when there’s little shade, no breeze, and warm water that discourages drinking.³
• Indoor heat during power failure: a home can become dangerous if cooling and airflow drop on a very hot day.³

Cats at higher risk

Any cat can overheat, but some carry the risk more easily, like a dark coat absorbing sun or a heavy body holding heat. Keep a closer watch if your cat is in one of these groups:^{1, 2}

• Flat-faced (brachycephalic) breeds (for example Persians and Exotic Shorthairs), who may struggle more with heat and breathing effort.²
• Older cats, very young kittens, and cats with underlying heart, airway, neurological, kidney or mobility problems.²
• Overweight cats and cats with thick or long coats (especially if matted).^{1, 2}

Symptoms of heatstroke in cats

Early warning signs

Early heat stress can be subtle. Often the first clue is a cat abandoning their usual routines and choosing the coolest surface they can find. Watch for:^{2, 3}

• panting or fast breathing (panting in cats is not normal and should be taken seriously)^{1, 5}
• drooling or thick saliva^{1, 3}
• restlessness, agitation, or suddenly hiding somewhere cool^{1, 6}
• weakness or lethargy^{1, 3}

Severe symptoms: treat as an emergency

When overheating progresses, the body starts to lose coordination and control. Seek urgent veterinary care immediately if you see:^{1, 2}

• vomiting and/or diarrhoea (sometimes with blood)¹
• bright red, very pale, or dark gums and tongue¹
• disorientation, staggering, or collapse^{1, 2}
• tremors or seizures^{1, 2}
• little to no urine, or coma/unconsciousness¹

Prevention: keeping heat from building up

Heatstroke prevention is mostly about the environment. On the hottest days, a safe cat is one who can choose shade, airflow and water without having to ask for it.^{3, 5}

Hot-weather basics (indoors and out)

• Never leave a cat in a car or ute. Even with windows cracked and parked in shade, the temperature can climb fast and become fatal.^{4, 7}
• Provide multiple water stations (in shade) and refresh them often; some cats drink more from a fountain or running source.³
• Offer shade and escape routes so your cat can move away from sun patches and hot rooms.^{3, 5}
• Check sheds, garages and outbuildings before closing doors—cats can be trapped quietly.³

Simple indoor cooling options

• Use air conditioning or a fan where possible, and keep airflow moving through the coolest part of the home.³
• Freeze a water bottle or ice pack, wrap it in a towel, and place it where your cat chooses to rest (not forcing contact).⁵
• Close blinds/curtains on sun-facing windows during the hottest part of the day to reduce radiant heat indoors.³

First aid: what to do if you think your cat has heatstroke

If you suspect heatstroke, start cooling straight away and organise urgent veterinary care. The aim is to bring body temperature down gradually while keeping breathing easy.^{1, 2}

Immediate steps

1. Move your cat into a cool, shaded or air-conditioned area.^{1, 3}
2. Begin gentle cooling with cool/tepid water (not ice-cold): wet the coat with cool water and increase airflow with a fan.^{1, 4}
3. Offer small sips of water if your cat is alert. Do not force them to drink.^{1, 3}
4. Call your vet or nearest emergency clinic and travel as soon as possible, continuing gentle cooling during transport if advised.^{1, 2}

What not to do

• Don’t use ice or ice-cold water and don’t submerge your cat in cold water; rapid overcooling can worsen the situation and increase the risk of shock.^{1, 4}
• Don’t wrap your cat tightly in wet towels and leave them there. Towels can warm up and trap heat unless they’re replaced often and paired with airflow.⁸
• Don’t wait for symptoms to “settle”. Heatstroke can cause internal injury that isn’t obvious at home.^{2, 4}

Veterinary treatment and recovery

At the clinic, treatment depends on severity. Vets commonly monitor temperature, breathing and circulation, and may provide oxygen and intravenous fluids to support hydration and organ perfusion while controlled cooling continues.^{1, 4}

Even after a cat appears brighter, vets may recommend observation and sometimes blood tests, because heat injury can affect organs and blood clotting later. Follow your vet’s home-care plan closely and keep your cat in a cool, quiet environment during recovery.²

Myths and misconceptions

“Cats are desert animals, so they can’t get heatstroke.”

Cats can still overheat, especially when humidity is high, airflow is poor, or they’re confined with no way to leave the heat. Panting in a cat should be treated as a warning sign, not a quirk.^{1, 5}

“Only outdoor cats are at risk.”

Indoor cats can be exposed during heatwaves, in sunrooms, laundries, and other enclosed spaces, or when cooling fails. A closed house can hold heat long after the sun moves on.³

“If I put a cold pack on them, that fixes it.”

The safest first aid is controlled, gradual cooling with cool/tepid water and airflow, followed by veterinary assessment. Ice and very cold water can do harm, and a quick improvement doesn’t rule out internal complications.^{1, 4}

Final thoughts

In summer, cats often look fine right up until they don’t. A little preparation—shade, water, airflow, and checking those easy-to-miss hot spaces—prevents most heat emergencies. If your cat starts panting or seems unsteady in the heat, cool them gently and get veterinary help quickly. It’s one of those moments where speed matters more than certainty.^{1, 3}

References

1. RSPCA Pet Insurance Australia – Heatstroke (Hyperthermia): signs, first aid and risk factors
2. PetMD – Heatstroke in Cats: signs, treatment and prevention
3. Cornell University College of Veterinary Medicine (Cornell Feline Health Center) – Feline heat safety
4. Merck Veterinary Manual – Emergency care for dogs and cats (Heat stroke section)
5. RSPCA NSW – Heat stress: prevention tips and first aid
6. Cats Protection – Heatstroke in cats: signs and what to do
7. RSPCA Australia – Five ways to keep your animals safe on hot days
8. EmergencyVET (Australia) – First aid for heat stroke in pets